Friday
May 24, 2013

# Homework Help: Science: Earth

physics
Solar luminosity is estimated to have been 30% lower than today at the time when the solar system formed, 4.6 billion years ago. (a) If Earth's albedo was the same as it is now (A=0.3), what would have been its effective radiating temperature Te at that time? (b) If the ...
Saturday, October 22, 2011 at 1:03am

Math
1. Many people know that the weight of an object varies on different planets, but did you know that the weight of an object on earth also varies according to the elevation of the object? In particular, the weight of an object follows this equation: , where C is a constant, and...
Friday, October 21, 2011 at 8:46pm

Math
1. Many people know that the weight of an object varies on different planets, but did you know that the weight of an object on earth also varies according to the elevation of the object? In particular, the weight of an object follows this equation: , where C is a constant, ...
Friday, October 21, 2011 at 8:40pm

Physics
A planet with mass 7 x 1024 kg orbits a sun with a period of 1 Earth's years. The speed of the planet around that sun is constant and |v|=43000 m/s. What is the mass of that sun?
Friday, October 21, 2011 at 4:59pm

biology
What are the major reservoirs of organic carbon on earth?
Friday, October 21, 2011 at 1:41am

physics
At a track-and-field meet, the best long jump is measured as 8.00 m. The jumper took off at an angle of 46° to the horizontal. (a) What was the jumper’s initial speed? (Neglect air resistance.) 1 m/s (b) If there were another meet on the Moon and the same jumper could...
Thursday, October 20, 2011 at 8:53pm

English
I urgently need your help to translate this school profile into English. Thank you. I included another sentence, too. 1) Students aged between sixteen and eighteen can opt for the bilingual branch (??) and study subject like Geographie/Earth Science, biology and history in ...
Thursday, October 20, 2011 at 4:54pm

earth
a satellite orbits the earth in circular orbit 620 km above the suface. if the radius of the earth is 6380 km, calculate, to 3 significanf figures, the distance travelled in a single orbit?
Thursday, October 20, 2011 at 1:20pm

physics numerical
a satellite orbitting the earth at the equator at a na ltitude of 400 km, has an antenna that can be modelled as a 2.0m long rod. the antenna is oriented perpndicular to the earth's surface. at the equator, the earth's magnetic field is essentially horizontal and has a...
Thursday, October 20, 2011 at 4:47am

physics
Take the mass of the Earth to be 5.98 × 1024 kg. If the Earth’s gravitational force causes a falling 74 kg student to accelerate downward at 9.8 m/s2, determine the upward acceleration of the Earth during the student’s fall. Answer in units of m/s2
Thursday, October 20, 2011 at 12:47am

science
Gravity on the surface of the moon is only 1/6 as strong as gravity on the Earth. What is the weight of a 15 kg object on the Earth? The acceleration of gravity is 10 m/s 2
Wednesday, October 19, 2011 at 9:45pm

Science
In what way is erosion NOT like weathering? A)It is a force that changes the earth's surface B)It is a destructive force C)It changes rocks in some way D)It breaks down rocks I think D??
Tuesday, October 18, 2011 at 6:19pm

Earth Science
Near shore, larger sand and gravel particles are moved along the ocean bottom by ____. a. deposition b. turbulence c. spits d. density currents
Tuesday, October 18, 2011 at 5:30pm

Math
You have 200 feet of fencing to enclose a rectangular plot that borders on a river. If you do not fence the side along the river, find the length and width of the plot that will maximize the area _____________________________________ Among all pairs of numbers whose sum is 20...
Tuesday, October 18, 2011 at 2:49pm

physics
light travels at a constant speed of 3x10^11 cm /sec how long does it take light to reach the earth a distance of 1.5x10^8 km give your answer in seconds and minutes.
Monday, October 17, 2011 at 9:39am

PHYSÝCS
Find the speed of a satellite in a circular orbit around the Earth with a radius 3.65 times the mean radius of the Earth; RE= 6.37·103 km ME= 5.98·1024 kg
Monday, October 17, 2011 at 9:33am

physics
A canoe has a velocity of 0.39 southeast relative to the earth. The canoe is on a river that is flowing 0.59 east relative to the earth. Find the magnitude of the velocity of the canoe relative to the river. Find the direction of the velocity of the canoe relative to the river
Monday, October 17, 2011 at 7:10am

Physics
A ferry is crossing a river. The ferry is headed due north with a speed of 2.8 m/s relative to the water and the river’s velocity is 4.9 m/s to the east. a) What is magnitude of the boat’s velocity relative to Earth
Monday, October 17, 2011 at 12:57am

Physics
A ferry is crossing a river. The ferry is headed due north with a speed of 2.8 m/s relative to the water and the river’s velocity is 4.9 m/s to the east. a) What is magnitude of the boat’s velocity relative to Earth
Monday, October 17, 2011 at 12:57am

AP environmental Science
What formula would i use to solve: If the earth has an annual growth rate of 1.2% how many people are added to the earth each year? what will be the population of earth in 2050? thanks, any help is appreciated!! :D
Sunday, October 16, 2011 at 10:17pm

astronomy
6. Suppose that you travel to a planet that has 4 times the Earth’s mass and 4 times the Earth’s radius. Calculate how much more or less you would weigh on this planet compared to your weight on Earth. Express your answer as a factor or fraction of your weight on ...
Sunday, October 16, 2011 at 10:03pm

geography
The question is - Into how many time zones is the Earth divided? My Answer is Twenty-Four time zones. Right? What is the approximate degrees of longitude for the International Date Line? My answer is 180 degrees longitude. Is this right? Thanks for all the help you have ever ...
Sunday, October 16, 2011 at 9:36pm

Physics
light travels at a constant speed of 3x10*11 cm/sec. how long does it take light to reach the earth a distance of 1.5x10*8 km. give the answers in seconds and minutes.
Sunday, October 16, 2011 at 7:56pm

physical
. On Earth the Mars rover had a weight of 9800 N. What will be its weight on mars where the acceleration due to gravity is 4 m/s
Sunday, October 16, 2011 at 6:24pm

physics
light travels at a constant speed of 3x10^11 centimeters/sec. how long does it take light to reach the earth a distance of 1.5x10^8 kilometers give your answer in seconds and minutes.
Saturday, October 15, 2011 at 2:16pm

Physics
Relative to the center of the Earth, the position of the Moon can be approximated by (t) = r [cos (ωt) + sin (ωt) ], where r = 3.84 108 m and ω = 2.46 10-6 radians/s. (a) Find the magnitude and direction of the Moon's average velocity between t = 0 and t = 3...
Saturday, October 15, 2011 at 2:11am

Physics 1 - Mechanics
You are making a trip in a space shuttle, and your friend Jimmy is in another space shuttle. He shares the same circular orbit with you, which is 420 km above the Earth, but he is 21 km ahead of you. (a) How long will it take you to catch up with your friend if you reduce your...
Friday, October 14, 2011 at 12:48pm

Physics 1 - Mechanics
You throw a rock with an initial horizontal velocity and it hits the ground at x meters away from your feet. What if: (a) You throw the same stone with the same initial conditions but instead you do this on a another planet with a mass 4 times the mass of the earth. With what ...
Friday, October 14, 2011 at 12:47pm

physics
A satellite orbits Earth once per day. From the reference frame of the Moon, which orbits Earth once about every 27 days, what is its motion?
Friday, October 14, 2011 at 10:33am

Calculus
Assume the world population will continue to grow exponentially with a growth constant (corresponding to a doubling time of about 52 years), it takes acre of land to supply food for one person, and there are 13,500,000 square miles of arable land in in the world. How long will...
Thursday, October 13, 2011 at 10:23pm

climate change
What would our climate be like if the earth was shaped like a cube instead of a sphere? thanks
Thursday, October 13, 2011 at 5:57pm

Physics
Which of the following involves a non-zero net force? I. A hockey-puck sliding at a constant speed on ice. II. The earth revolving around the sun at a constant speed. III. An object falling near the surface of the earth. A) I only B) III only C) Both I and II D) Both II and ...
Thursday, October 13, 2011 at 5:42pm

physics
The earth orbits the sun once every 365.24 days. The distance between the earth and sun is 1.49x 10^8 Km. The mass of the earth is 5.96 x 10 ^24 kg. A) Find the magnitude in newtons of the centripetal force acting on the earth. The mass of mars is 6.56 x 10 ^23 Kg and the ...
Wednesday, October 12, 2011 at 9:44pm

physics
Average destance between Earth and the moon is 384 790 km. How many days would it take sound to travel to the moon?
Wednesday, October 12, 2011 at 9:15pm

Math WORD PROBLEM
The time in hours it takes a satellite to complete an orbit around the earth varies directly as the radius of the orbit (from the center of the earth) and inversely as the orbital velocity. If a satellite completes an orbit 860 miles above the earth in 12 hours at a velocity ...
Wednesday, October 12, 2011 at 8:49pm

Geometry
An engineer designed a 620 ft long water canal to drain a rainwater detention pond. It is to have a trapezoid cross-section that is 8 ft deep, 15 ft across the bottom, with walls sloping outward at an angle of 40. (a)Calculate the volume of earth that needs to be ...
Wednesday, October 12, 2011 at 5:21pm

Astronomy/Physics
I cannot calculate the gravitational force between these two objects. I am confused. Jupiter (R=800 million km, M = 2 x 10 to the 27th power kg and a 100 kg person on earth. Please help!
Wednesday, October 12, 2011 at 3:22pm

physics
( 1.) An objectis thrown upward from the edge of a tall building with a velocity of 10m/s. Where will the object be 3s after it is thrown? Take g = 10m/s^2 15m above the top of the building 30m below the top of the building 15m below the top of the building 30m above the ...
Wednesday, October 12, 2011 at 11:59am

Astronomy
Imagine that Earth did not turn on its axis. (a) What would be true about the ecliptic? It would now define the day rather than the year. It would still be defined and could be seen from all points on Earth, but only when they faced the sun. It would still be defined, but only...
Tuesday, October 11, 2011 at 7:52pm

physics
A rocket consists of a payload of 4280.0 kg and 1.626 105 · of fuel. Assume that the rocket starts from rest in outer space, accelerates to its final velocity, and then begins its trip. What is the speed at which the propellant must be expelled to make the trip from the...
Tuesday, October 11, 2011 at 9:44am

science
churvas mass is 66kg. find his weight on earth and on the moon.
Tuesday, October 11, 2011 at 7:35am

science
churvas mass is 66kg. find his weight on earth and on the moon.
Tuesday, October 11, 2011 at 7:33am

DUMANGEZE
A 0.04KG BEAD SLIDES ON A CURVED STARTING FROM REST AT POINT A.THE EARTH FROM A AND B IS FRICTIONLESS ,WHILST THE PATH FROM B TO C IS ROUGH.IF THE BEAD ARRIVES AT POINT C WITH A SPEED OF 1M/S DERTIMINETHE AMOUNT OF WORKDONE BY THE FRICTIONAL FORCE IN PASSING FROM B TO C?
Tuesday, October 11, 2011 at 6:38am

PHYSICS
In a particular region of Earth's atmosphere, the electric field above Earth's surface has been measured to be 151 N/C downward at an altitude of 280 m and 167 N/C downward at an altitude of 430 m. Calculate the volume charge density of the atmosphere, assuming it to ...
Monday, October 10, 2011 at 7:59pm

physics
A ferry is crossing a river. If the ferry is headed due North with speed of 2.5m/s relative to the water and the river's velocity is 3 m/s to the east, what will the boat's velocity be relative to Earth?
Monday, October 10, 2011 at 6:47pm

English
Thank you. Do you say "he will become Thane of Cowdor OR the Thane of Cowdor? I looked up prophesy in the dictionary and found out that it can be both a noun or a verb. (to Prophesy: to say what will happen in the future, especially using religious or magical knowledge...
Monday, October 10, 2011 at 6:39pm

physics
The Earth moves toward you through what distance? (Assume the seat is 45.0 cm high.)
Monday, October 10, 2011 at 3:37pm

World History
With the adoption of Christianity by Constantine, the emperor A. was no longer worshipped as a god. B. was called God's deputy on Earth. C. stopped using images of pagan gods. D. ended pagan rituals and ceremonies. My answer is B. but i am not quiet sure is i am correct.
Monday, October 10, 2011 at 11:30am

physics
Because Earth's rotation is gradually slowing, the length of each day increases: The day at the end of 1.0 century is 1.0 ms longer than the day at the start of the century. In 58 centuries, what is the total (in hours) of the daily increases in time (that is, the sum of ...
Monday, October 10, 2011 at 11:29am

Physics
A man of mass 75.5 kg walks down the aisle of an airplane at a speed of 1.50 m/s in the forward direction while the plane moves at a speed of 305 m/s relative to the earth. (a) Find the man's kinetic energy relative to the plane. (b) Find the man's kinetic energy ...
Monday, October 10, 2011 at 9:43am

Physics
In a particular region of Earth's atmosphere, the electric field above Earth's surface has been measured to be 151 N/C downward at an altitude of 280 m and 167 N/C downward at an altitude of 430 m. Calculate the volume charge density of the atmosphere, assuming it to ...
Sunday, October 9, 2011 at 5:50pm

physics
a man weighs 573 n on earth. what would he weigh on Jupiter, where the free-fall acceleration is 25.9 m/s 2nd power? the acceleration of gravity is 9.8 m/s 2nd power? the acceleration of gravity is 9.8 m/s 2nd power.
Sunday, October 9, 2011 at 5:18pm

Electric Fields
In a particular region of Earth's atmosphere, the electric field above Earth's surface has been measured to be 151 N/C downward at an altitude of 280 m and 167 N/C downward at an altitude of 430 m. Calculate the volume charge density of the atmosphere, assuming it to ...
Sunday, October 9, 2011 at 5:08pm

science
Sam weighs 720 N on earth and 120 N on the moon. What does this tell you about the value of gravity on the moon?
Sunday, October 9, 2011 at 2:12pm

physics 12
If the Earth has a mass of 5.98*10^24 kg and orbits the Sun at a radius of 1.43*10^11 meters. Find the mass of the Sun. Thank you.
Friday, October 7, 2011 at 5:47pm

earth
Some people have proposed building a giant elevator from Earth's surface to geosynchronous orbit. The top of the elevator would then have the same orbital distance and period as any satellite in geosynchronous orbit. Suppose you were to let go of an object at the top of ...
Friday, October 7, 2011 at 2:21pm

Physics
A satellite has a mass of 99 kg and is located at 1.97 106 m above the surface of Earth. (a) What is the potential energy associated with the satellite at this location? Answer in J (b) What is the magnitude of the gravitational force on the satellite? Answer in N
Thursday, October 6, 2011 at 11:01pm

physics
An airplane with a speed of 85.1 m/s is climbing upward at an angle of 54.4 ° with respect to the horizontal. When the plane's altitude is 759 m, the pilot releases a package. (a) Calculate the distance along the ground, measured from a point directly beneath the point...
Thursday, October 6, 2011 at 6:47pm

Earth Science
If an unstable isotope contained 5 protons and 8 neutrons, how many neutrons would need to decay to make the unstable isotope stable? Please Help!
Thursday, October 6, 2011 at 6:04pm

Physical science
A satellite that is 4175 miles from the center of the earth, orbits with a period of 90 minutes. What is its centripetal acceleration?
Thursday, October 6, 2011 at 2:44pm

physical science
A satellite that is 4175 miles from the center of the earth, orbits with a period of 90 minutes. What is its centripetal acceleration?
Thursday, October 6, 2011 at 2:40pm

Physics
The strength of gravity on Mars is only 40% of that on earth. If a child has a mass of 30 kg on earth, what would the child's weight be on Mars? . I came up with 120N is this right?
Wednesday, October 5, 2011 at 8:14pm

physics
A 29 kg child, with a 4.5 kg backpack on his back, first stands on a sidewalk and then jumps up into the air. Find the magnitude and direction of the force on the sidewalk from the child when the child is (a) standing still and (b) in the air. Now find the magnitude and ...
Tuesday, October 4, 2011 at 12:07pm

Physics
After the Sun exhausts its nuclear fuel, its ultimate fate may be to collapse into a white dwarf state. In this state, it would have approximately the same mass as it has now, but its radius would be equal to the radius of earth. (a) Calculate the average density of the white ...
Tuesday, October 4, 2011 at 1:12am

physics
The Earth rotates on its own axis once per day (24.0h). What is the tangential speed of the summit of Mt. Kilimanjaro (elevation 5895 m above sea level), which is located approximately on the equator, due to rotation of the Earth? The equatorial radius of Earth is 6378 km.
Monday, October 3, 2011 at 1:08am

Astronomy
Jupiter is farther from the sun than is the Earth. In the course of several earth years what phases would you expect jupiter to exhibit to an observer on earth. explain
Sunday, October 2, 2011 at 11:39pm

English 1301
So I think I just might be over thinking these run-on sentences, but I keep second guessing myself and need some help with these sentences: 1. Death Valley National Monument, located in California and Nevada, is one of the hottest places on Earth, temperatures there have ...
Sunday, October 2, 2011 at 11:22pm

earth
A satellite moves in a circular orbit about our earth exactly four times a day. Find its orbit, radius , speed and weight.
Sunday, October 2, 2011 at 9:34pm

physics
a jet airliner moving initially at 3..00X10^2 mi/h due east enters a region where the wind is blowing 1.0 x 10^2 mi/h in a direction 30 degrees north of east. A) find the components of the velocity of the jet airliner relative to the air. b) find the components of the velocity...
Sunday, October 2, 2011 at 6:20pm

Geology
Winds blow whenever there are: cold temperatures, pressure inequalities in the atmosphere, or the earth rotates on its axis
Sunday, October 2, 2011 at 5:47pm

earth
Which process could lead directly to the formation of pumice rock?
Sunday, October 2, 2011 at 4:30pm

Astronomy
The average distance between the Earth and the Sun is called the astronomical unit (AU), which is about 150 million km (1.5 x 108 km). Jupiter is 780 million km from the sun. a) How far is Jupiter from the sun in astronomical units (AU)? b) Based on your calculation in part a...
Sunday, October 2, 2011 at 12:21pm

Astronomy
Suppose that you travel to a planet that has 4 times the Earth's mass and 4 times the Earth's radius. Calculate how much more or less you would weigh on this planet compared to your weight on Earth. Express your answer as a factor or fraction of your weight on Earth. ...
Saturday, October 1, 2011 at 11:24pm

Physics
Posted earlier but I wrote it incorrectly. How fast would a rocket have to be going in order to completely leave the solar system? (Assume that the Sun is the only mass in the solar system and that the rocket is beginning its journey from Earth's orbit?)
Friday, September 30, 2011 at 1:46pm

Physics
How fast would a rocket have to be going in order to completely leave the solar system? (For the second part of this problem, assume that the Sun is the only mass in the solar system and that the rocket is beginning its journey from Earth's orbit?)
Friday, September 30, 2011 at 1:39pm

science
How far away from the earth does acceleration due to gravity become 1% of its value at the earth's surface. Assume that the earth is a sphere of radius 638000000cm.
Friday, September 30, 2011 at 11:48am

Physics
How fast does a rocket need to be going to break free of Earth's gravity? How fast would it have to be going in order to completely leave the solar system? (For the second part of this problem, assume that the Sun is the only mass in the solar system and that the rocket is...
Friday, September 30, 2011 at 9:56am

Find the resultant force on (a) the mass m1 = 0.183 kg and (b) the mass m2 = 0.106 kg (the masses are isolated from the earth).. The first mass is 400kg and its 10 cm from the second mass which is 0.183 kg (m1). the second mass is 10 cm away from the third mass which is 0.106 ...
Thursday, September 29, 2011 at 10:45pm

Physics
How fast does a rocket need to be going to break free of Earth's gravity? How fast would it have to be going in order to completely leave the solar system? (For the second part of this problem, assume that the Sun is the only mass in the solar system and that the rocket is...
Thursday, September 29, 2011 at 10:11pm

physics
Suppose a person weighs 160 pounds on Earth. How much would that person weigh on a planet that was three times as massive as Earth and had a radius that was twice that of Earth's?
Thursday, September 29, 2011 at 10:05pm

earth
Compared with the strength of Earth's gravity at its surface, how much weaker is gravity at a distance of 11 Earth radii from Earth's center?
Thursday, September 29, 2011 at 12:14pm

physics
why does saturn have smaller density than earth and mars which is smaller than saturn?
Thursday, September 29, 2011 at 9:16am

ivcc
What is the magnitude of the apparent weight of a 76 astronaut 3200 from the center of the Earth's Moon in a space vehicle accelerating toward the Moon at 3.6 ?
Wednesday, September 28, 2011 at 9:58pm

physics
The Earth’s radius is about 6380 km. The space shuttle is orbiting about 300.1 km above Earth’s surface. If the average speed of the space shuttle is 25700 km/h, ﬁnd the time required for it to circle Earth. Answer in units of h
Wednesday, September 28, 2011 at 8:40pm

English
Thank you very much. I wrote a few more sentences for you to check. 1)Under Henry VII England enjoyed a fairly long spell (I need a synonym) of unbroken peace and prosperity. 2) In particular, a mercantile fleet was created whereas the army and the navy were reorganized and ...
Wednesday, September 28, 2011 at 1:45pm

Physics
A 0.28-kg stone is held 1.5 m above the top edge of a water well and then dropped into it. The well has a depth of 4.8 m. (a) Taking y = 0 at the top edge of the well, what is the gravitational potential energy of the stone–Earth system before the stone is released? J (b...
Tuesday, September 27, 2011 at 7:09pm

chem
the atom of element A has 2 electrons in its highest energy level N. a)what is the special name given to elements in the same gp as A? i answered as alkali earth metal because the valence electron is 2. am i right?
Tuesday, September 27, 2011 at 11:48am

Algebra 1 Scientific Notation
Isaac newtons theory of universal gravitation states that the equation F=G m^1m^2/r^2 can be used to calculate the amount of gravitational forces in newtons between 2 point masses (m^1) and (m^2) separated by a distance (r). G is a constant equal to 6.67*10^-11 m^2 kg^-2. The ...
Monday, September 26, 2011 at 10:34pm

what is Microbiologist ? I have to name 4 things that tell me what it is
Monday, September 26, 2011 at 9:20pm

physics
The acceleration due to gravity on planet X is one fifth that on the surface of the earth. If it takes 4.6 s for an object to fall a certain distance from rest on earth, how long would it take to fall the same distance on planet X? Answer in units of s
Monday, September 26, 2011 at 7:10pm

earth
The acceleration due to gravity on planet X is one fifth that on the surface of the earth. If it takes 4.6 s for an object to fall a certain distance from rest on earth, how long would it take to fall the same distance on planet X? Answer in units of s
Monday, September 26, 2011 at 7:10pm

Physics
Gravity on the surface of the moon is only 1 6 as strong as gravity on the Earth. What is the mass of a 30 kg object on the Earth? The acceleration of gravity is 10 m/s
Monday, September 26, 2011 at 4:35pm

physics
I am so confused How fast (in km/hr) must a plane fly along the Earth's equator so that the Sun stands still relative to the passengers. The radius of the Earth is 6400 km
Monday, September 26, 2011 at 2:55pm

Physical Science
1. In which of the following units is acceleration expressed? *A. Newtons B. Foot-pounds C. Kilograms D. Meters per second squared 2. A stone falls from a ledge and takes 16 seconds to hit the ground. The stone has an original velocity of 0 m/s. How tall is the ledge? A. 1,254...
Monday, September 26, 2011 at 2:17pm

earth
Find the ratio of the gravitational attraction between (a)a man of mass 100 kg and a woman of mass 50 kg who is 10 meters away from him and (b) the attraction between the woman and the Earth.
Monday, September 26, 2011 at 1:43pm

Science
How is the water in icebergs involved in the water cycle on Earth?
Monday, September 26, 2011 at 8:16am

University Physics
A 320.0 m tall tower is built on the Equator. How much faster (in m/s) does a point at the top of the tower move than a point at the bottom. The radius of the Earth is 6400 km.
Monday, September 26, 2011 at 3:02am

english
separate the sentence with a line between the complete subject and the complete predicate Three-fourths of the earth / is covered by water, and most of it is salty ocean water. is the line in this simple sentence correct?? THANKS
Sunday, September 25, 2011 at 6:25pm

physics
a projectile is fired from the surface of the earth with a speed of 200 m/s at an angle of 30 degrees above the horizontal. If the ground is level, what is the maximum height reached by the projectile
Sunday, September 25, 2011 at 6:03pm

physics
suppose that all the people of the earth went to the north pole and on a signal all jump straight up. estimate the recoil speed of the earth. the mass of the earth is 6 x 10^24 kg and there are about 6 billion people(6 x 10^9).
Sunday, September 25, 2011 at 10:50am

physics
At the surface of Mars, the acceleration due to gravity is 3.72 m/s^2. A watermelon has a mass of 4.5 kg here on Earth. a) What is its weight here on earth? b) What is its mass in Mars? c)What is its weight in Mars?
Sunday, September 25, 2011 at 2:34am

diffirential calculus
two points are moving horizontally in space at different heights above the earth. show that the angle of elevation of the line joining them is greater when the distance between them is least.
Sunday, September 25, 2011 at 12:23am

Early Earth was constantly being bombarded by meteorites, comets, and asteroids. Was early Earth an open system or a closed system? Explain your answer.
Saturday, September 24, 2011 at 6:20pm

Earth/Space Science
What effect, if any, would you expect a massive forest fire to have on the amount of carbon dioxide in the atmosphere? Explain your answer, please?
Saturday, September 24, 2011 at 5:55pm

physics
need help with the following question. if earth has a mass of 6.0*10^24 kg and a radius 6.4*10^6 m: a) find the change in gravitational potential energy of a meteorite of mass 150 kg as it moves from an infinite distance to the earth's surface. b) with what speed does the ...
Saturday, September 24, 2011 at 6:39am

Physics
a particle (C) of mass m = 0.2 kg can slide without friction on an inclined plane making an angle alfa (a) = 30 degrees with respect to the horizontal (aka ground) . (C) is launched at at an instant to=0 along a line Ox of greatest slope with an initial velocity of Vo =5 m/s...
Saturday, September 24, 2011 at 4:48am

geometry
write a biconditional for: the moon is the largest satellite of Earth.
Wednesday, September 21, 2011 at 8:03pm

Earth Science
Were there any lessons learned from the Valdez Spill that helped contain the devastation of the BP spill in the gulf?
Wednesday, September 21, 2011 at 2:32pm

College Physics
When searching for gold, measurements of g can be used find regions within the Earth where the density is larger than that of normal soil. Such measurements can also be used to find regions in which the density of the Earth is smaller than normal soil; such regions might ...
Wednesday, September 21, 2011 at 12:16am

Physics
Suppose the density of the Earth was somehow reduced from its actual value to 1300 kg/m3. What would be the value of g, the acceleration due to gravity, on this new planet? Assume the radius does not change. I know that density = mass/volume & the volume of a sphere = 4/3pir^3...
Tuesday, September 20, 2011 at 9:42pm

Physics
We saw in Example 5.7 how a centrifuge can be used to separate cells from a liquid. To increase the speed at which objects can be separated from solution, it is useful to make the centrifuge’s speed as large as possible. If you want to design a centrifuge of diameter 68 ...
Tuesday, September 20, 2011 at 9:38pm

maths
Q1) Paul brought a car last year. It has lost 12½% of its value since then. It is now valued at £10,500 How much did Paul pay for his car? -[I got £11812.50... Is that right?~xD] Q2) A newspaper report stated: "Concorde has flown 7.1x10^7 miles. This is...
Tuesday, September 20, 2011 at 12:13pm

geography
Does a line of latitude or a line of longitude divide the Earth into Northern and Southern Hemispheres? This is an easy one but I just want to double check. The answer is a line of latitude. Right?
Monday, September 19, 2011 at 10:30pm

Physics
On a distant planet, golf is just as popular as it is on earth. A golfer tees off and drives the ball 4.3 times as far as he would have on earth, given the same initial velocities on both planets. The ball is launched at a speed of 40 m/s at an angle of 46° above the ...
Monday, September 19, 2011 at 9:02pm

REALLY EASY
Which of the following explanations correctly describes the reason we see the Sun rise and set each day? 1.The Sun rotates on its axis 2.The Earth revolves around the Sun in an elliptical path 3.The Earth rotates on its axis 4.The Sun revolves around the Earth in an elliptical...
Monday, September 19, 2011 at 8:27pm

REALLY EASY
Which of the following are a consequence of the Earth's yearly motion around the Sun? (check all that apply) 1.the Sun appears in different constellations in different seasons 2.the planets look different than stars 3.the Sun rises and sets 4.the Moon exhibits phases 5....
Monday, September 19, 2011 at 8:26pm

physics
a ferry is crossing a river. If the ferry is headed due north with a speed of 2.5 meters per second relative to the water and the river's velocity is 3 meters per second to the east, what will the boat's velocity be relative to earth?
Monday, September 19, 2011 at 7:17pm

science
Suppose a new drill could reach twice as far in the earth's crust as a drill can today. How would this affect rocks?
Monday, September 19, 2011 at 6:23pm

Earth Science
What are FIVE tools that we use to help us extend our senses when making quantitative observations?
Sunday, September 18, 2011 at 4:23pm

English
Thank you very much. Can you check the word choice in the following sentences, too? Thank you. 1) With the death of Elizabeth in 1603 the Tudor line died out and James VI (1603-1625) became the first Stuart King in England. 2) James I believed that the monarch was the ...
Sunday, September 18, 2011 at 2:04pm

geometry
whats the Biconditional of "the moon is the largest satellite of Earth"
Sunday, September 18, 2011 at 1:43pm

trig
A space shuttle 200 miles above the earth is orbiting the. Earth once every 6 hours. how far does the shuttle travel in one hour? Note the radius of earth about 4000 miles.
Saturday, September 17, 2011 at 9:19pm

Physics
The acceleration due to gravity on the moon is about one sixth its value on earth. If a baseball reaches a height of 62 m when thrown upward by someone on the earth, what height would it reach when thrown in the same way on the surface of the moon? Answer in units of m
Saturday, September 17, 2011 at 9:05pm

physics
( If a person can jump a maximum horizontal distance (by using a 45° projection angle) of 1.33 m on Earth, what would be his maximum range on the Moon, where the free-fall acceleration is g/6 and g = 9.80 m/s2?
Saturday, September 17, 2011 at 6:38pm

Physics
On the earth, you throw an object up in the air at some velocity, v, and it reaches a maximum vertical displacement (max. height if you prefer) of 4.8 meters. If you went to the moon, where the value of the gravitational acceleration of the moon is 1/6 of that on earth, and ...
Friday, September 16, 2011 at 2:24pm

earth
a student measures the velocity of a water in a stream as 2.5 meters pe second.the actual velocity of the water is 3.0 meters per second. what is the approximate percent deviation of the studen's measurement
Thursday, September 15, 2011 at 10:16pm

physicssssss
A blue ball is thrown upward with an initial speed of 20.6 m/s, from a height of 0.8 meters above the ground. 2.5 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 8.2 m/s from a height of 23.7 meters above the ground. The force of ...
Thursday, September 15, 2011 at 9:23pm

physics
A blue ball is thrown upward with an initial speed of 20.6 m/s, from a height of 0.8 meters above the ground. 2.5 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 8.2 m/s from a height of 23.7 meters above the ground. The force of ...
Thursday, September 15, 2011 at 5:12pm

physics
A ball is thrown upward. After reaching a maximum height, it continues falling back to- ward Earth. On the way down, the ball is caught at the same height at which it was thrown upward.If the time (up and down) the ball remains in the air is 2.3 s, find its speed when it ...
Thursday, September 15, 2011 at 4:12pm

English check please I've corrected it again
. Dispatch 2. Orient 3. Enigma 4. Discern 5. Enhance 6. Attribute 7. Nocturnal 8. Exemplify 9. Mobile 10. Attest Animals Possess sensory powers that humans lack. Homing pigeons fly with great speed and accuracy when 1)___(e)d with messages to faraway places. How do Pigeons 2)...
Wednesday, September 14, 2011 at 1:12pm

English Correction
My answers: 1. Dispatch 2. Discern 3. Enigma 4. Orient 5. Enhance 6. Attribute 7. Nocturnal 8. Exemplify 9. Mobile 10. Attease Animals Possess sensory powers that humans lack. Homing pigeons fly with great speed and accuracy when 1)___(e)d with messages to faraway places. How ...
Wednesday, September 14, 2011 at 12:03pm

earth and space
the grams on the moon is different then space ?
Wednesday, September 14, 2011 at 11:30am

math
earth diameter is 13000 kilometers, globe diameter of0.5 meter, what is the globes scale as a ratio. What distance on Earth would 1 cm on the globe represent?
Wednesday, September 14, 2011 at 9:29am

Earth/Space Science
Some scientists have hypothesized that meteorites have periodically bombarded Earth and caused mass extinctions every 26 million years. How might this hypothesis be tested?
Tuesday, September 13, 2011 at 9:41pm

Earth
Some scientists have hypothesized that meteorites have periodically bombarded Earth and caused mass extinctions every 26 million years. How might this hypothesis be tested?
Tuesday, September 13, 2011 at 9:01pm

Physics I
An Earth satellite moves in a circular orbit 770 km above the Earth's surface. The period of the motion is 100.0 min. What is the speed of the satellite? What is the magnitude of the centripetal acceleration of the satellite?
Tuesday, September 13, 2011 at 8:19pm

Word Problems
Will someone please write an expression for these? I am horrible at this, i will solve them though. 1.) Logan withdrew \$32 from her bank account. After her withdrawal, her balance was \$8. How much was originally in her account? 2.)The baseball birthday batter package at a ...
Tuesday, September 13, 2011 at 3:36pm

English
Could you please check these two sentences, please? 1) Water chute and spring board don't have the same meaning, but I think I can use them both with "dive into the water". 2) Superman was both a superhero endowed with superpowers and a shy and insecure ...
Tuesday, September 13, 2011 at 10:37am

Physics
A rocket is launched from rest. After 8.0 min, it is 160 Km above the Earth’s surface and is moving at a speed of 7.6 Km/s. Assuming the rocket moves up in a straight line, what are its (a) average velocity and (b) average acceleration?
Tuesday, September 13, 2011 at 7:25am

phy
A blue ball is thrown upward with an initial speed of 20.6 m/s, from a height of 0.8 meters above the ground. 2.5 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 8.2 m/s from a height of 23.7 meters above the ground. The force of ...
Tuesday, September 13, 2011 at 12:22am

geography
Into how many degrees of longitude is the Earth divided? My answer is 360 degrees. Am I correct?
Monday, September 12, 2011 at 10:22pm

Social Studies
How are these facts contribute to life on earth? *Gravity holds the sun together. *The sun is about 4.5 billion years old. *The sun is by far the largest object in the solar system.
Monday, September 12, 2011 at 8:47pm

physics
At a point high in the Earth’s atmosphere, He 2+ ions in a concentration of 2.8 X 1012/m3 are moving due north at a speed of 2.0 X 105 m/s. Also, a 7.0 X 1011/m3 concentration of O2 ions is moving due south at a speed of 7.2 X 106 m/s. Determine the magnitude and ...
Monday, September 12, 2011 at 7:27pm

Science
A satellite orbiting at an elevation of 3200 km does what a) Stays beyond the earth's gravity, which is why it stays up there. B) in an elliptical orbit, since its speed is less than the escape velocity. C) Falling toward earth with an acceleration equal to g. D) Falling ...
Sunday, September 11, 2011 at 9:42pm

Science
what would tides be like if the moon did not exist? a) There would be no tides without the moon's gravity. b) There would be one high tide and one low tide every 24 hours because of the sun's gravity, with the high tide at noon and the low tide at midnight. c) There ...
Sunday, September 11, 2011 at 9:19pm

Science
Why doesn't the space station fall toward the earth, instead of remaining in space? a) It is beyond the earth's gravitational pull. B) The earth's gravity is balanced out by the attraction of the sun and other planets. C) Centrifugal force keeps it up. D) It does ...
Sunday, September 11, 2011 at 8:32pm

Algebtra
from 630 feet at the top of the horizon. Due to the curvature of the earth how far away is the city. using d=sqrt[3h/2] where d is the distance in nautical miles and h is the height in feet.
Sunday, September 11, 2011 at 7:14pm

Earth/Space Science
Explain why scientific ideas that have been subject to many tests are still considered theories and not scientific laws.
Saturday, September 10, 2011 at 11:58pm

Science
Can someone please help me with these questions below thank you. 1. What do you think the impact of the earth's climate will be like if everyone enjoyed the same lifestyle? 2. What will it be like for The health of ecosystems and biodiversity? 3. What will the impact be ...
Saturday, September 10, 2011 at 9:10pm

Physics
A rocket starts from rest and moves upward from the surface of the earth. For the first 10s of its motion, the vertical acceleration of the rocket is given by a_y =( 2.70m/s^3)t, where the +y-direction is upward. 1) What is the height of the rocket above the surface of the ...
Saturday, September 10, 2011 at 8:26pm

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