Friday

April 18, 2014

April 18, 2014

Number of results: 24,524

**ALGEBRA 2**

A plane takes off from an aiport and flies east at a speed of 350 mi/h. Ten minutes later, a second plane takes off from the same airport and flies east at a higher altitude at a speed of 400 mi/h. How long does it take the second plane to overtake the first plane? I have ...
*Sunday, August 16, 2009 at 4:40pm by Emily*

**PHYSICS**

An entertainer juggles balls while doing other activities. In one act, she throws a ball vertically upward, and while it is in the air, she runs to and from a table 5.50m away at a constant speed of 2.50m/s, returning just in time to catch the falling ball. (a)With what ...
*Tuesday, July 13, 2010 at 7:14am by Francis*

**math**

A man is walking at an average speed of 4 miles per hour alongside a railroad track. A freight train, going in the same direction at an average speed of 30 miles per hour, requires 5 seconds to pass the man. How long is the freight train? Give your answer in feet. What would ...
*Tuesday, October 5, 2010 at 3:40pm by Amy*

**Physics**

Two cars are approaching one another in the same lane of a highway. One has a speed of 30m/s, the other a speed of 20m/s when they are 96m apart. The drivers simultaneously apply brakes to avert a collision. Both cars lose speed at 6.0m/s^2. How long after the application of ...
*Wednesday, February 20, 2008 at 12:08am by Anonymous*

**Physics**

A bicycle starts at the origin of a circular track that has a circumference of 126 m and travels at a constant speed a distance s = 38.0 m in a time t = 12s. a)what is the angular displacement (in rad) of the bicycle from its starting position? r=20.1 so theta or angular ...
*Monday, April 16, 2007 at 11:00pm by Anderson*

**physics**

A passenger on a moving train tosses a coin with an initial velocity of (-2.25 m/s) + 4.68 m/s) (from the point of view of the passenger). The train's velocity relative to the ground is (11.5 m/s). (a) What is the minimum speed of the coin relative to the ground during its ...
*Sunday, September 16, 2012 at 6:37pm by maria*

**pre-cal**

a pilot wants to fly on a bearing of 66.4 degrees. by flying due east, he finds that a 57-mph wind, blowing from the south, puts him on course. Find the airspeed of the plane. Sketch this. He flys east unknown speed. The plane goes at 66.4, unknown speed. The N vector is 57 ...
*Tuesday, June 5, 2007 at 10:05pm by brandy*

**Physics**

A 79.0-kg fullback running east with a speed of 4.00 m/s is tackled by a 93.0-kg opponent running north with a speed of 3.00 m/s. (a) Why does the tackle constitute a perfectly inelastic collision? (b) Calculate the velocity of the players immediately after the tackle. ...
*Tuesday, October 4, 2011 at 12:29pm by Allie*

**Physics**

Let the distance from A to B (in meters) be L. The total distance travelled is then 2L The times spend going back and forth are L/20 and L/25 s. Divide 2L by [L/20 + L/25] for the average speed. Note that the L cancels out. Vav = 2/[1/20 + 1/25] = 2/(9/100) = ___ m/s Note that...
*Tuesday, January 19, 2010 at 6:58pm by drwls*

**Physics**

A 23-kg boy stands 3 m from the center of a frictionless playground merry-go-round, which has a moment of inertia of 180 kg m2. The boy begins to run in a circular path with a speed of 0.6 m/s relative to the ground. (a) Calculate the angular velocity of the merry-go-round in ...
*Monday, June 18, 2012 at 7:33pm by Maria*

**physic**

A girl throws a stone from a bridge. Consider the following ways she might throw the stone. The speed of the stone as it leaves her hand is the same in each case. Case A: Thrown straight up. Case B: Thrown straight down. Case C: Thrown out at an angle of 45° above horizontal. ...
*Wednesday, July 21, 2010 at 1:40pm by lisa*

**Psysik**

From the top of a tower is an object of mass 25 kg lowered at constant speed, 4 m / s with a rope to the ground. After 10 seconds of the rope breaks, and the object falls freely. From the moment (the rope breaks) there is 12 seconds to those standing on top of the tower and ...
*Monday, October 18, 2010 at 12:28pm by OddbjÃ¸tn*

**Physics**

You are riding on a jet ski directed at an angle upstream on a river flowing with a speed of 2.8 m/s. If your velocity relative to the ground is 8.9 m/s at an angle of 26.0° upstream, what is the speed of the jet ski relative to the water? (Note: Angles are measured relative ...
*Sunday, October 14, 2012 at 2:17pm by HELP PLEASE*

**physics**

In a game of pool the cue ball strikes another ball of the same mass and initially at rest. After the collision the cue ball moves at 3.50 m/s along a line making an angle of 22 degrees with its original direction of motion. and the second ball had a speed of 2 m/s. a)What is ...
*Sunday, March 4, 2007 at 9:28am by Chris*

**last physics problem!**

A ball of mass 522 g starts at rest and slides down a frictionless track, as shown below. It leaves the track horizontally, striking the ground a distance x = 0.93 m from the end of the track after falling a vertical distance h2 = 1.18 m from the end of the track. (a) At what ...
*Thursday, April 15, 2010 at 5:32pm by brittany*

**Physics**

A gull is flying horizontally 8.17 m above the ground at 6.35 m/s. The bird is carrying a clam in its beak and plans to crack the clamshell by dropping it on some rocks below. Ignoring air resistance, what is the horizontal distance to the rocks at the moment that the gull ...
*Thursday, September 20, 2012 at 1:11pm by Josh*

**Physics**

A gull is flying horizontally 8.17 m above the ground at 6.35 m/s. The bird is carrying a clam in its beak and plans to crack the clamshell by dropping it on some rocks below. Ignoring air resistance, what is the horizontal distance to the rocks at the moment that the gull ...
*Saturday, September 22, 2012 at 2:55pm by Kasey*

**Physics**

A gull is flying horizontally 8.17 m above the ground at 6.35 m/s. The bird is carrying a clam in its beak and plans to crack the clamshell by dropping it on some rocks below. Ignoring air resistance, what is the horizontal distance to the rocks at the moment that the gull ...
*Sunday, September 23, 2012 at 11:12am by Liz*

**Physics**

A small aircraft takes off and accelerates for 1 min at the rate of 1.5m/s^2. it then maintains a constant flying speed for 20mins after which it lowers its flaps, descends and reduces its speed uniformly, coming to rest in 45secs. Using a separate sheet of paper, if necessary...
*Monday, February 18, 2008 at 2:54pm by Anonymous*

**Math **

This is also another problem that I'm having trouble on. A motorboat can maintain a constant speed of 16 miles per hour relative to the water. The boat makes a trip upstream to a certain point in 20 minutes; the return trip takes 15 minutes. What is the speed of the current? ...
*Thursday, September 16, 2010 at 12:47am by amy*

**Physics**

The ball spins at 7.7 rev/s. In addition, the ball is through with a linear speed of 19 m/s at an angle of 55 degrees with respect to the ground. If the ball is caught at the same height at which it left the quarterback's hand, how many revolutions has the ball made in the air...
*Monday, December 21, 2009 at 8:39pm by Christopher*

**Physics**

A cyclist approaches the bottom of a gradual hill at a speed of 20 m/s. The hill is 4.4 m high, and the cyclist estimates that she is going fast enough to coast up and over it without peddling. Ignoring air resistance and friction, find the speed at which the cyclist crests ...
*Monday, February 25, 2008 at 11:12pm by Zach*

**Physics**

A 46.0 kg man stands on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of 1.85 m/s in 1.07 s. It travels with this constant speed for the next 6.80 s. The elevator then slows down (undergoes a uniform acceleration in the ...
*Friday, September 9, 2011 at 7:26pm by Elisabeth*

**Physics**

A baggage carousel at an airport is rotating with an angular speed of 0.397 rad/s when the baggage begins to be loaded onto it. The moment of inertia of the carousel is 2440 kg·m2. Ten pieces of baggage with an average mass of 16.5 kg each are dropped vertically onto the ...
*Monday, January 27, 2014 at 10:10pm by Sam*

**Physics**

A baggage carousel at an airport is rotating with an angular speed of 0.397 rad/s when the baggage begins to be loaded onto it. The moment of inertia of the carousel is 2440 kg·m2. Ten pieces of baggage with an average mass of 16.5 kg each are dropped vertically onto the ...
*Monday, January 27, 2014 at 10:40pm by Ben*

**physics**

The eye of a hurricane passes over Grand Bahama Island. It is moving in a direction 60.0° north of west with a speed of v1 = 42.0 km/h. Exactly three hours later, the course of the hurricane shifts due north, and its speed slows to v2 = 24.0 km/h, as shown in Figure 3-30. How ...
*Saturday, September 11, 2010 at 12:17am by stef*

**physics**

A 3Kg projectile is fired straight upward from earth's surface with a speed that is one-fourth the escape speed. Neglecting air resistance. a) What is the Kinetic energy of this projectile when it is launched? b) what is the gravitational potential energy of this projectile ...
*Monday, February 14, 2011 at 7:47pm by rick*

**Astronomy**

Try some of the following links: http://search.yahoo.com/search?fr=mcafee&p=what+determines+orbital+speed Sra
*Sunday, August 29, 2010 at 1:39pm by SraJMcGin*

**science**

Try some of the following links; http://search.yahoo.com/search?fr=mcafee&p=how+to+determin+e+the+speed+of+a+wave Sra
*Thursday, May 19, 2011 at 2:38pm by SraJMcGin*

**physics**

A 27-kg boy stands 4 m from the center of a frictionless playground merry-go-round, which has a moment of inertia of 238 kg m2. The boy begins to run in a circular path with a speed of 0.6 m/s relative to the ground. (a) Calculate the angular velocity of the merry-go-round. (...
*Saturday, March 26, 2011 at 10:56pm by Really stuck in this problem !!*

**physics**

Eris, the largest dwarf planet known in the Solar System, has a radius R = 1200 km and an acceleration due to gravity on its surface of magnitude g = 0.77 m/s2. (a) Use these numbers to calculate the escape speed from the surface of Eris. 1360 m/s correct answer. (b) If an ...
*Sunday, October 30, 2011 at 9:15pm by mymi*

**Physics**

With what speed relative to the rocks does the clam smash into the rocks? and With what speed relative to the gull does the clam smash into the rocks?
*Thursday, September 20, 2012 at 1:07pm by Lisa*

**Physics **

According to the Guinness Book of World Records (1990 edition, p. 169), the highest rotary speed ever attained was 2010 m/s (4500 mph). The rotating rod was 15 cm (5.9 in) long. Assume the speed quoted is that of the end of the rod. What is the centripetal acceleration of the ...
*Sunday, January 13, 2013 at 9:42pm by Emily*

**Physics**

speed north = 30 - 130 sin 30 = -35 speed west = 130 cos 30 = 113 tan angle south of west = 35/113 so angle south of west = 17.2 deg so 270 - 17.2 = 253 on the compass rose
*Saturday, February 15, 2014 at 6:59pm by Damon*

**Physics**

Consider a roller coster car moving along a track from point A to point B to point C. a)if the roller coaster car starts from rest at point A (30m above the bottom of a dip (point b). What would be the speed of the car at the top of the next hill (point C), which is 20 m above...
*Wednesday, October 17, 2007 at 8:52pm by Andrea*

**Physics**

An arrow is fired with a speed of 20.0 m/s at a block of Styrofoam resting on a smooth surface. The arrow penetrates a certain distance into the block before coming to rest relative to it. During this process the arrow's deceleration has a magnitude of 1300 m/s2 and the block'...
*Monday, October 12, 2009 at 12:34pm by Robert C*

**Physics - 2-D kinematics**

A soccer ball is kicked with an initial horizontal velocity of 20 m/s and an initial vertical velocity of 16 m/s. I've calculated: Initial Speed: 25.61 m/s Angle: 38.66 degrees Maximum Height it reaches: 13.06 m Distance kicked: 65.29m NOW I NEED: What is the speed of the ball...
*Friday, February 3, 2012 at 4:37pm by Anonymous*

**physics**

if the height of a playground slide is kept constant, will the length of the slide or the presence of bumps make any difference in the final speed of kids playing on it if a) the slide is frictionless b) the slide has kinetic friction? a) if the slide is frictionless, length ...
*Monday, October 30, 2006 at 9:40pm by nicole*

**ict**

Thank you for using the Jiskha Homework Help Forum. Besides the fact that you would need a computer, or I-Phone, etc. you would need either a dial-up service or a cable service, software... Here are some sites on the Internet that may help you: 1. (Wikipedia): http://en....
*Monday, September 15, 2008 at 5:10am by SraJMcGin*

**Algebra**

Let V be the speed going out and then 2V is the speed coming back Time coming back = time going out - 5 280/2V = 280/V - 5 Solve that equation for V
*Sunday, May 25, 2008 at 3:44pm by drwls*

**Physics Urgent!!!**

The 1994 Winter Olympics included the aerials competition in skiing. In this event skiers speed down a ramp that slopes sharply upward at the end. The sharp upward slope launches them into the air, where they perform acrobatic maneuvers. In the women's competition, the end of ...
*Thursday, February 1, 2007 at 7:50pm by Samantha*

**Physics: merry-go-round question**

A playground merry-go-round of radius 1.92 m has a moment of inertia 411 kg m2 and is rotating at 10.4 rev/min. A child with mass 38.3 kg jumps on the edge of the merry-go-round. Assuming that the boy's initial speed is negligible, what is the new angular speed of the merry-go...
*Monday, April 26, 2010 at 7:00pm by Tessa*

**math**

celia writes the equation d=8t to represent the distance in miles d thaat bikers could travel in t hours at a speed of 8 miles per hour... make a table that shows the distance traveled every half hour/up to 5 hours/if bikers ride at the costant speed? This is what the table ...
*Monday, October 2, 2006 at 9:35pm by chemiii*

**Physics/Astronomy**

A pulsar is a stellar object that emits light in short bursts. Suppose a pulsar with a speed of 0.975c approaches Earth, and a rocket with a speed of 0.999c heads toward the pulsar (both speeds measured in Earth’s frame of reference). If the pulsar emits 20.0 pulses per second...
*Thursday, April 25, 2013 at 2:01am by Kim*

**Physics**

Mario, a hockey player, is skating due south at a speed of 6.6 m/s relative to the ice. A teammate passes the puck to him. The puck has a speed of 12.9 m/s and is moving in a direction of 23° west of south, relative to the ice. What are the magnitude and direction (relative to...
*Wednesday, October 9, 2013 at 2:19pm by Mario*

**Physics**

In January 2004, NASA landed exploration vehicles on Mars. Part of the descent consisted of the following stages: Stage A: Friction with the atmosphere reduced the speed from 19300 to 1600 in 4.0 . Stage B: A parachute then opened to slow it down to 321 in 94 . Stage C: Retro ...
*Friday, May 28, 2010 at 1:40pm by Anonymous*

**Physics**

In the figure below, an electron is moving rightward between two parallel charged plates separated by distance d = 2.40 mm. The particle is speeding up from an initial speed of 3620 km/s at the left plate. ｜ ｜ &#...
*Thursday, January 31, 2013 at 9:53pm by ann*

**algebra**

Not sure how you got your answer, but it is one minute off. Speed going = 24 miles /(36/60) houre = 40 miles per hour return speed = 40+5 = 45 miles per hour Time required = 24 miles / 45 mph * 60 minutes/hour = 32 minutes.
*Sunday, April 17, 2011 at 8:28pm by MathMate*

**Physics**

a) 145 km/h = 40.28 m/s You want to reduce the speed to 90 km/h = 25.00 m/s The time T that it takes to decelerate to the lower speed at the fasted deceleration rate, a = 4.2 m/s^2, is given by 25 = 40.28 - a T T = (40.28-25)/a = 3.64 s b) Graph V = 40.28 - 4.2 t (in m/s) If ...
*Monday, June 13, 2011 at 9:33pm by drwls*

**Calc**

A student is in a 20 week calc class. The function f(t)=50-50e^0.2t f(t) measures the students problem speed in t weeks -how many problems per hour can a student solve at the beginning of the course - how many problems per hour can a student solve halfway through the course -...
*Friday, July 20, 2012 at 2:07pm by Marshall*

**Physics**

In a World Cup soccer match, Juan is running due north toward the goal with a speed of 7.70 relative to the ground. A teammate passes the ball to him. The ball has a speed of 13.3 and is moving in a direction of 30.5 east of north, relative to the ground. a) what is the ...
*Tuesday, September 25, 2012 at 8:34pm by Annie*

**Classical Mechanics Physics - Urgent help please**

da can u help m for above question rocket onsider a rocket in space that ejects burned fuel at a speed of vex= 2.0 km/s with respect to the rocket. The rocket burns 11 % of its mass in 250 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a burn...
*Saturday, December 7, 2013 at 5:46pm by kumar*

**physics**

Three identical balls are thrown from a cliff of height, h, above a horizontal plane. One ball is thrown at an angle of 45 degrees above the horizon, the second is thrown horizontally, and the third is thrown at an angle of 30 degrees below the horizon (so, part of this ...
*Wednesday, December 2, 2009 at 3:31pm by William*

**physics**

Three identical balls are thrown from a cliff of height, h, above a horizontal plane. One ball is thrown at an angle of 45 degrees above the horizon, the second is thrown horizontally, and the third is thrown at an angle of 30 degrees below the horizon (so, part of this ...
*Friday, December 11, 2009 at 8:15am by Kelly*

**physics**

Halley's comet moves about the sun in an elliptical orbit with its closest approach to the SUn being .59AU and its greatest distance being 35AU (1AU=Earth-sun distance) if the comet's speed at closest approach is 54km/s what is its speed when it is farthest from the Sun? you ...
*Monday, January 29, 2007 at 4:20pm by cyndi*

**Physics**

At what temperature is the rms speed of helium molecules half its value at STP (0 C, 1.0 atm})?(answer in K) I think i need to use V_rms=sqrt3kT/m k=1.38e^-23J/K helium has 4g so i think helium molecule is 4/6.02e23 but i don't know how to proceed further then i have to answer...
*Sunday, November 22, 2009 at 1:46am by ana*

**Physics**

F*r = I * a Where F is the force on the merry-go-round, r is the radius, I is the moment of inertia of the merry-go-round, and a is the angular acceleration for a solid, horizontal disk, the moment of inertia is: 1/2*m*r^2 F*r = 1/2*m*r^2*a F = 1/2*m*r*a w = w0 + a*t where w ...
*Thursday, November 1, 2012 at 1:29pm by Jennifer*

**math**

1 revolution = 2 pi radians so 5 revs/sec * 2 pi radians/rev = 31.4 rad/s which is called omega, the angular velocity r = radius = 42 cm = .42 m speed at rim = omega r speed = 31.4 rad/s * .42 m = 13.2 m/s convert now 13.2 m/s (3600 s/hr)(1 km/1000m) = 47.5 km/hr
*Wednesday, December 25, 2013 at 10:36am by Damon*

**physics**

1)As a sound source moves away from a stationary observer, the number of waves will. decrease 2)How fast should a car move toward you for the car's horn to sound 2.88% higher in frequency than when the car is stationary? The speed of sound is 343 m/s. fs(v-vd/v-vs) 343(1/1-987...
*Sunday, April 6, 2008 at 8:44pm by Jon*

**Basic algebra**

Speed = r mi/h going to work. Speed = (r+10)m/h returning. d = r mi/h * 1 h = (r+10)mi/h * 0.5h r * 1 = (r+10) * 0.5 r = 0.5r + 5 0.5r = 5 r = 10 mi/h r+10 = 10+10 = 20 mi/h d = 10 * 1 = (10+10) * 0.5 = 10 mi.
*Tuesday, March 4, 2014 at 1:59pm by Henry *

**Physics**

A long-range jet liner flies (almost exactly) level at constant speed, subject to the forces of drag fD=(1/2)CDrhoSv^2, thrust Ft, and weight Mg. Given the plane's wing area, lift and drag coefficients, speed and takeoff mass, calculate the engine power required for level ...
*Tuesday, May 10, 2011 at 12:42pm by Ferdinand*

**Physics**

A long-range jet liner flies (almost exactly) level at constant speed, subject to the forces of drag fD=(1/2)CDrhoSv^2, thrust Ft, and weight Mg. Given the plane's wing area, lift and drag coefficients, speed and takeoff mass, calculate the engine power required for level ...
*Tuesday, May 10, 2011 at 4:15pm by Ferdinand*

**physics**

A horizontal spring attached to a wall has a force constant of 800 N/m. A block of mass 1.10 kg is attached to the spring and oscillates freely on a horizontal, frictionless surface as in the figure below. The initial goal of this problem is to find the velocity at the ...
*Tuesday, September 27, 2011 at 7:54pm by Anonymous*

**Physics**

A pilot must fly his plane to a town which is 200 km from his starting point in a direction 30 degrees N of E. He must make the trip in 1/2 hr. An 80km/h wind blows in a direction 30 degrees E of S. Find the speed of the plane relative to the ground, the speed relative to air ...
*Saturday, March 1, 2008 at 11:40am by Anonymous*

**Vibration and Wave Fundamentals**

Vibration and Wave Fundamentals 1. A machine gun fires 10 rounds per second. The speed of the bullets is 300 m/s. (A.) What is the distance in the air between the flying bullets? ____ ANSWER=30 (B.)What happens to the distance between the bullets if the rate of fire is ...
*Sunday, January 24, 2010 at 2:06pm by Sam*

**physics**

A mass m is attached to the end of a spring (constant k). The mass is given an initial displacement x0 from equilibrium, and an initial speed v0. Ignoring friction and the mass of the spring, use energy methods to find the following in terms of the given quantities. (Use x_0 ...
*Sunday, November 7, 2010 at 5:08pm by Lily*

**physics**

A mass M of 2.95 kg is attached to the end of a string whose length is 0.420 m. The mass slides without friction on a horizontal surface as indicated in the diagram. If the string can withstand a maximum tension of 127.5 N, what is the maximum tangential speed the ball can ...
*Wednesday, October 16, 2013 at 8:48pm by Anonymous*

**Classical Mechanics - Need Help Please**

woooooooooo thx @Hw !did u got this correct Consider a rocket in space that ejects burned fuel at a speed of vex= 2.0 km/s with respect to the rocket. The rocket burns 11 % of its mass in 250 s (assume the burn rate is constant). (a) What is the speed v of the rocket after a ...
*Sunday, December 8, 2013 at 3:38am by kumar*

**AP PHYSICS**

A stone is tied to a string (length = 0.450 m) and whirled in a circle at the same constant speed in two different ways. First, the circle is horizontal and the string is nearly parallel to the ground. Next, the circle is vertical. In the vertical case the maximum tension in ...
*Wednesday, October 27, 2010 at 6:26pm by PLEASE HELP NEED IT PLEASE*

**physics**

65.0-kg person throws a .045kg snowball forward with a ground speed of 30.0 m/s. a second person with a mass of 60.0-kg catches the snowball. both people are on skates. the first person is intially moving forward wit ha speed of 2.50 m/s and the second person is initially at ...
*Tuesday, November 2, 2010 at 10:16pm by bailey*

**physics (help)**

A meteorite of mass m= 1 ×104 kg is approaching head-on a planet of mass M= 3 ×1029 kg and radius R= 7 ×104 km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed v0= 2 ×102 km/s. Take G= 6.67 ×10−11. Determine the speed ...
*Friday, November 1, 2013 at 8:54am by Anonymous*

**Physics**

Your question is missing some units 8.9 what? 8.9 miles per hour? 8.9 feet per second? To find the distance in inches that Larry runs you multiply average speed * time, but you first might have to do some conversions to make sure units are compatible. For example if Larry's ...
*Tuesday, October 2, 2012 at 11:26pm by Jennifer*

**math**

Cindy starts at 2pm, when Eric has already been cycling for two hours. Distance apart at 2pm = 150-2*18 =114 miles The sum of their speeds =18+12 =30 mph They will meet when the distance divided by the total speed equals 114 miles, or time = 114/30 = 3.8 hours after 2 pm. ...
*Tuesday, October 12, 2010 at 4:22pm by MathMate*

**PHYSICS **

A car is safely negotiating an unbanked circular turn at a speed of 29 m/s. The road is dry, and the maximum static frictional force acts on the tires. Suddenly a long wet patch in the road decreases the maximum static frictional force to one-ninth of its dry-road value. If ...
*Tuesday, October 2, 2012 at 9:18pm by Lindsay*

**phy**

A ball of mass 0.540 kg moving east (+x direction) with a speed of 3.30 m/s collides head-on with a 0.740 kg ball at rest. If the collision is perfectly elastic, what will be the speed and direction of each ball after the collision? a)ball originally at rest m/s b)ball ...
*Thursday, October 7, 2010 at 7:40pm by ami*

**physics**

A pelican ﬂying along a horizontal path drops a ﬁsh from a height of 6.0 m. The ﬁsh travels 7.7 m horizontally before it hits the water below. What was the pelican’s initial speed? The acceleration of gravity is 9.81 m/s 2. If the pelican was traveling at ...
*Tuesday, October 9, 2012 at 10:37pm by David*

**Physics... Please Help**

An arrow is fired with a speed of 20.0 m/s at a block of Styrofoam resting on a smooth surface. The arrow penetrates a certain distance into the block before coming to rest relative to it. During this process the arrow's deceleration has a magnitude of 1300 m/s2 and the block'...
*Wednesday, October 14, 2009 at 1:46pm by Robert C*

**Maths**

Lower quartile=39, Upper quartile=63. Measurements of wind speed on a certain island were taken over a period of one year. A box-andwhisker plot of the data obtained is displayed above, and the values of the quartiles are as shown. It is suggested that wind speed can be ...
*Sunday, September 30, 2012 at 6:34am by Pipipapoo*

**phical science**

Neutrinos are almost massless, travel close to the speed of light, and pass through matter almost undisturbed. Photons, on the other hand, have no mass, travel at the speed of light, yet are absorbed and/or reflected even by fairly sparse matter such as gasses. A photon has an...
*Monday, March 18, 2013 at 8:54am by Elena*

**College Algebra**

Average speed = total distance traveled/total time taken time for first leg of trip =200/55 hrs time for second leg of trip = 200/40 hours so average speed = 400/(200/55 + 200/40) =46.3 mph
*Monday, November 19, 2007 at 11:42pm by Reiny*

**physics**

Two gears A and B are in contact. The radius of gear A is twice that of gear B. (a) when A’s angular velocity 6.00 Hz counter clockwise, what is B’s angular velocity? (b) If A’s radius to the tip of the teeth is 10.0 cm what is the linear speed of a point on the tip of a gear ...
*Monday, October 3, 2011 at 1:21am by John*

**AP Physics**

A stone is tied to a string (length = 0.450 m) and whirled in a circle at the same constant speed in two different ways. First, the circle is horizontal and the string is nearly parallel to the ground. Next, the circle is vertical. In the vertical case the maximum tension in ...
*Tuesday, October 26, 2010 at 12:22pm by AP Physics*

**Physics**

A pendulum consists of a 2.6 kg stone swinging on a 4.5 m string of negligible mass. The stone has a speed of 7.9 m/s when it passes its lowest point. (a) What is the speed when the string is at 53 ¢ª to the vertical? (b) What is the greatest angle with the vertical that the ...
*Thursday, October 25, 2012 at 3:15pm by Cody*

**Physics**

An electron is accelerated through a uniform electric field of magnitude 2.5x10^2 N/C with an initial speed of 1.2x10^6 m/s parallel to the electric field. a) Calculate the work done on the electron by the field when the electron has travelled 2.5 cm in the field. b) Calculate...
*Tuesday, April 21, 2009 at 5:29pm by Linn*

**Physics kinematics**

time to top = 4.5/2 = 2.25 seconds vertical velocity v = Vo + a t at top v = 0 0 = Vo - 9.8 (time to top) Vo = 9.8 (2.25) Vo = 22.05 sin 63 = 22.05/speed speed = 22.05/ .891 =24.7
*Thursday, March 13, 2008 at 10:17pm by Damon*

**Math**

Average speed = total distance/total time time for first leg = 8/5 hrs time for 2nd leg = 2/7 hours total time = 8/5 + 2/7 or 66/35 avg speed = 10/(66/35) = 10(35/66) = 5.3 mph
*Tuesday, February 15, 2011 at 4:03am by Reiny*

**physics**

A person walking with a speed of 1.44 m/sec releases a ball from a height of h = 1.28 m above the ground. Use the point on the ground, directly below where the ball is initially released at the origin of your coordinate system. (a) What is the ball's position at 0.25 seconds ...
*Sunday, September 11, 2011 at 6:21pm by Katie*

**Physics**

A ball of radius 0.300 m rolls along a horizontal table top with a constant linear speed of 3.30 m/s. The ball rolls off the edge and falls a vertical distance of 2.50 m before hitting the floor. What is the angular displacement of the ball while it is in the air? (All ...
*Tuesday, April 24, 2007 at 2:49pm by Mary*

**Uniform Motion**

The vertical motion and the horizontal motion are decoupled. The vertical velocity is v = 3 m/s and the vertical acceleration is 0 m/s^2 In the horizontal plane the speed is u = 2 pi r/T = 2 pi (8/5) = 10 m/s and the acceleration is centripetal = v^2/r = 12.6 m/s^2 toward the ...
*Friday, September 26, 2008 at 1:38pm by Damon*

**calculus**

(a) time = distance/speed, so a trip of 1000km takes 1000/v hours. So, the cost is c(v) = (1000/v)(160 + 1/100v^3) (b) Now just find minimum cost where dc/dv = 0 dc/dv = 20(v^3-8000)/v^2 so minimum cost when v=20 (c) Since min occurs at v=20, if top speed is 16, then minimum ...
*Sunday, November 17, 2013 at 8:37am by Steve*

**math a little less**

celia writes the equation d=8t to represent the distance in miles d that bikers could travel in t hours at a speed of 8 miles per hour. make a table that shows the distance traveled every half hour,up to 5 hours if bkikers ride at this constant speed. how far would bikers ...
*Monday, October 2, 2006 at 9:54pm by chemiii*

**physics**

A trapeze artist sailing through the air rotates with a rotational speed of 0.9·rev/s. If she contracts to reduce her rotational inertia to one sixth of what it was, what will her new rotational speed be? _____ rev/s? Can she completely stop her rotation while still airborne? ...
*Wednesday, February 6, 2013 at 6:25pm by wally*

**Physics ( Calculus & Mecahnics ) **

A proton with mass m moves in one dimension.The potential-energy function is where and are positive constants. The proton is released from rest a x0 = a/b. (a) Show that can be written as U(x) = a --- [ ( x0/x )^2 - x0/x ] x0^2 Graph U(x). Calculate U(x0) and thereby locate ...
*Sunday, January 23, 2011 at 10:26pm by Clark*

**physics**

An elevator without a ceiling is ascending with a constant speed of 9.7 m/s. A boy on the elevator shoots a ball directly upward, from a height of 2.0 m above the elevator floor, just as the elevator floor is 25 m above the ground. The initial speed of the ball with respect to...
*Tuesday, September 21, 2010 at 11:48pm by kay*

**math**

A motorcycle leaves Colorado Springs traveling north at an average speed of 47 miles per hour. One hour later, a car leaves Colorado Springs traveling south at an average speed of 54 miles per hour. How long after the motor cycle leaves will it take until they are 552 miles ...
*Tuesday, May 31, 2011 at 2:17pm by elaine*

**Physics**

Water flowing through a garden hose of diameter 2.77 cm fills a 25.0-L bucket in 1.40 min. (a) What is the speed of the water leaving the end of the hose? Answer in m/s (b) A nozzle is now attached to the end of the hose. If the nozzle diameter is one-third the diameter of the...
*Sunday, March 30, 2014 at 3:41pm by Renee*

**Physics**

Water flowing through a garden hose of diameter 2.77 cm fills a 25.0-L bucket in 1.40 min. (a) What is the speed of the water leaving the end of the hose? Answer in m/s (b) A nozzle is now attached to the end of the hose. If the nozzle diameter is one-third the diameter of the...
*Sunday, March 30, 2014 at 7:13pm by Renee*

**Physic**

Water flowing through a garden hose of diameter 2.77 cm fills a 25.0-L bucket in 1.40 min. (a) What is the speed of the water leaving the end of the hose? Answer in m/s (b) A nozzle is now attached to the end of the hose. If the nozzle diameter is one-third the diameter of the...
*Sunday, March 30, 2014 at 8:21pm by Renee*

**Physics - important**

An electron is accelerated through a uniform electric field of magnitude 2.5x10^2 N/C with an initial speed of 1.2x10^6 m/s parallel to the electric field. a) Calculate the work done on the electron by the field when the electron has travelled 2.5 cm in the field. b) Calculate...
*Tuesday, April 21, 2009 at 7:46pm by Linn*

**Physics**

Speed of Asteroids With the same Radius? Two spherical asteroids have the same radius R . Asteroid 1 has mass M and asteroid 2 has mass 2M. The two asteroids are released from rest with distance 10R between their centers. What is the speed of each asteroid just before they ...
*Tuesday, April 12, 2011 at 9:06pm by Dan*

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