Thursday

February 11, 2016
Total # Posts: 572

**physics**

The moon has a mass of 7.35 E 22 kg and is located 3.84 E 8 meters from the Earth. If Ellen, an earthling, has a mass of 47 kg, what is the gravitational force between Ellen and the moon?
*April 21, 2010*

**physcs**

A potter's wheel having a radius 0.55 m and a moment of inertia 11.6 kg·m2 is rotating freely at 55 rev/min. The potter can stop the wheel in 8.0 s by pressing a wet rag against the rim and exerting a radially inward force of 66 N. Find the effective coefficient of ...
*April 17, 2010*

**physics**

thanks again
*April 17, 2010*

**physics**

A rubber ball filled with air has a diameter of 25.1 cm and a mass of 0.618 kg. What force is required to hold the ball in equilibrium immediately below the surface of water in a swimming pool? I tried using the equation B = density(fluid)volume(object)g B = 1.0E3(4/3(pi)(....
*April 17, 2010*

**physics**

oh wow, thanks.... wish I would have thought of that. it worked.
*April 10, 2010*

**physics**

A satellite moves in a circular orbit around Earth at a speed of 4390 m/s (a) Determine the satellite's altitude above the surface of Earth.(meters) (b) Determine the period of the satellite's orbit. (hours) I used the equation M(sattelite)V^2/r = M(sattelite)(Mass(...
*April 10, 2010*

**physics**

I tried to use V^2/r = GM(earth)/r^2 but I am not getting the correct answer.
*April 7, 2010*

**physics**

A satellite moves in a circular orbit around Earth at a speed of 4390 m/s. (a) Determine the satellite's altitude above the surface of Earth. m (b) Determine the period of the satellite's orbit. h am I supposed to use rotational equations for this? I don't know ...
*April 7, 2010*

**physics**

Objects with masses of 190 kg and a 490 kg are separated by 0.380 m. (a) Find the net gravitational force exerted by these objects on a 57.0 kg object placed midway between them. N (b) At what position (other than infinitely remote ones) can the 57.0 kg object be placed so as ...
*April 5, 2010*

**highschool anatomy**

During what period of life does immunocompetence develop?
*March 29, 2010*

**physics**

(a) What is the tangential acceleration of a bug on the rim of a 6.0 in. diameter disk if the disk moves from rest to an angular speed of 79 rev/min in 5.0 s? (b) When the disk is at its final speed, what is the tangential velocity of the bug? (c) One second after the bug ...
*March 28, 2010*

**physics**

and for the second one, i took the rad/s and multiplied it times .1524m to get m/s and it said i was incorrect again.
*March 27, 2010*

**physics**

well, for the first one, I changed the rev/s to rad/s which was 8.275 rad/s and then i divided that by 5s to get the angular acceleration and then mulitiplied it by the radius (.1524m) in order to change it to tangential acceleration but it said my answer was incorrect.
*March 27, 2010*

**physics**

(a) What is the tangential acceleration of a bug on the rim of a 6.0 in. diameter disk if the disk moves from rest to an angular speed of 79 rev/min in 5.0 s? m/s2 (b) When the disk is at its final speed, what is the tangential velocity of the bug? m/s (c) One second after the...
*March 27, 2010*

**physics**

A car initially traveling at 31.0 m/s undergoes a constant negative acceleration of magnitude 2.00 m/s2 after its brakes are applied. (a) How many revolutions does each tire make before the car comes to a stop, assuming the car does not skid and the tires have radii of 0.330 m...
*March 27, 2010*

**Physics**

never mind.
*March 24, 2010*

**Physics**

A dentist's drill starts from rest. After 3.00 s of constant angular acceleration it turns at a rate of 2.8 104 rev/min. (a) Find the drill's angular acceleration. (b) Determine the angle (in radians) through which the drill rotates during this period.
*March 24, 2010*

**Physics**

A skier of mass 76 kg is pulled up a slope by a motor-driven cable. (a) How much work is required to pull him 40 m up a 30° slope (assumed frictionless) at a constant speed of 2.5 m/s? J I know that the answer to the first problem is 14896Joules, but I do not know how to ...
*March 10, 2010*

**algebra**

multiply both sides by six which gives you 3xa = 12 then divide by 3 which gives you xa = 4 then if you are solving for x, divide both sides by a which gives you x = 4/a if you are solving for a, do the oppisite.
*March 10, 2010*

**physics**

Two blocks, A and B (with mass 50 kg and 100 kg, respectively), are connected by a string. (one mass is on the incline, the other is hanging from the pullye) The pulley is frictionless and of negligible mass. The coefficient of kinetic friction between block A and the incline ...
*March 10, 2010*

**Physics**

Thank you SO much! I didn't realize i had to do 27(1-cos33)
*March 10, 2010*

**Physics**

Tarzan swings on a 27.0 m long vine initially inclined at an angle of 33.0° with the vertical. (a) What is his speed at the bottom of the swing if he starts from rest? (b) What is his speed at the bottom of the swing if he pushes off with a speed of 3.00 m/s? I tried to ...
*March 10, 2010*

**physics**

never mind, I figured it out.
*March 10, 2010*

**physics**

A 770 N man stands in the middle of a frozen pond of radius 9.0 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 1.2 kg physics textbook horizontally toward the north shore at a ...
*March 10, 2010*

**physics**

When an automobile moves with constant speed down a highway, most of the power developed by the engine is used to compensate for the mechanical energy loss due to frictional forces exerted on the car by the air and the road. If the power developed by the engine is 195 hp, ...
*March 10, 2010*

**Physics**

I drew the sketch, the problem does not tell me how high he is initially, I can find the equation vfinal = the square root of (2gh) but I don't know what h is.
*March 10, 2010*

**Physics**

Tarzan swings on a 27.0 m long vine initially inclined at an angle of 33.0° with the vertical. (a) What is his speed at the bottom of the swing if he starts from rest?(b) What is his speed at the bottom of the swing if he pushes off with a speed of 3.00 m/s?
*March 10, 2010*

**Physic**

Ok so this question was posted before but I'm confused by the answer. The problem is: The two masses (m1 = 5.0 kg and m2 = 3.0 kg) in the Atwood's machine shown in Figure 10-23 are released from rest, with m1 at a height of 0.87 m above the floor. When m1 hits the ...
*March 8, 2010*

**6th grade**

For every 25 mm of rain falling on the avarage home, 5000 L runs off the roof. Some people use barrels to collect this rain water. Cecila's town usually has 2625mm of rain each year. How many litres of water can be collected by using barrels?
*March 8, 2010*

**Spanish**

We are learning Indirect object pronouns and I need help with the following questions. Traduce las frases al espanol. 11. He asked her for more money. 12. I gave you your present. 13. She bought you a new dress. 14. He prepared dinner for us. 15. Musicals fascinate me. 16. She...
*March 8, 2010*

**Chemistry 101**

I don't remember my instructor going over this and the book isn't explaining it very well. Can anyone help answer these? Indicate the concentration of each ion or molecule present in the following solutions. 1. 0.30 M NaNO3 2. 1.5x10^-2 M MgSO4 3. 2.00x10-2 M C6H12O6 4...
*February 22, 2010*

**Chemistry help**

I'm not sure how to answer this question.... Assume that magnesium would act atom-for-atom exactly the same as copper in this experiment. How many grams of magnesium would, have been used in the reaction if one gram of silver were produced? The atomic mass of magnesium is ...
*February 15, 2010*

**Chem answer check **

Does this look correct? Thx! Write the balanced equation for the reaction between solid copper and silver nitrate, that produces solid silver and copper(II) nitrate in solution. Include your experimentally determined mole ratios for the copper and silver atoms as coefficients...
*February 15, 2010*

**1st grade**

3 facts about motion
*February 10, 2010*

**geometry**

how do i find the perimeter of a triangle with missing measurements? i have no clue how to do this!
*February 7, 2010*

**precalculus**

A man is walking away from a lamppost with a light source h = 6 m above the ground. The man is m = 1.5 m tall. How long is the man's shadow when he is d = 11 m from the lamppost? (Hint: Use similar triangles.)
*January 12, 2010*

**9th grade algebra**

what times what is equal to 37
*December 9, 2009*

**spanish 2**

cmplete this rule with hay que or se prohibe 1. almorzar en la sala de clase 2 respetar a los demas 3. entregar la tarea a tiempo 4. ir al armario durante las clases 5 contestar las preguntas del profesor
*December 3, 2009*

**GEOMETRY **

I think you mean "diagonal," not "diagnol."
*November 13, 2009*

**English**

You must have missed my second response. I changed my answer, therefore I assumed you were responding to that.
*November 13, 2009*

**English**

That's what I was thinking Thank you
*November 13, 2009*

**English**

Can you please explain to me how drinking tea is "effective and relevant" to getting good results? I don't understand.
*November 13, 2009*

**English**

paying attention?
*November 13, 2009*

**English**

Something that is tangential to getting good results: a. drinking tea b. proper planning c. paying attention d. working hard a. drinking tea?
*November 13, 2009*

**cooking**

nothing it just makes the recipe cook longer and soggier
*November 13, 2009*

**chemistry**

What is the density (in g/L) of hydrogen gas at 23.0 degrees Celsius and a pressure of 1670 psi?
*November 3, 2009*

**English**

My teacher says to take booknotes on To Kill a Mockingbird but I don't know what booknotes are?
*October 27, 2009*

**Proper Grammer**

I am just editing my essay for my one class and this is a question I always get stumped on which is the proper way. Would a comma or period go inside the quotation marks, or outside? Example, "The dog ran extremely fast." "The dog ran extremely fast". and I...
*October 6, 2009*

**math**

At what rate will $150 double itself in 14 years? Hoe do I solve this?
*September 22, 2009*

**algebra 1A**

5 less than 3 plus y and x
*September 17, 2009*

**6th science**

scienctist who stidy the natural world say that there is unity in diversity. how does this idea apply to plants?
*September 15, 2009*

**8th grade science**

Measurement is a quantity with both a ____________________? Please fill in the blank. This question is on my study guide and I do not know what the answer is?
*September 2, 2009*

**Algebra**

Consider the graph of the equation y=ax^2+bx+c, when a does not equal 0. If a is multiplied by 3, what is true of the graph of the resulting parabola? (A) The Vertex is 3 units above the vertex of the original. (B) The new parabola is wider than the original. (C) The new ...
*May 14, 2009*

**5th grade social studies**

1 is Christopher Columbus
*April 15, 2009*

**math**

What is the probability of selecting a boy and a girl if their are 7 girls and 3 boys.
*April 6, 2009*

**math**

how do you find a unit price? is there a formula you need to follow? ex.)how would i find a unit price on an ice cream that if 14 Fl. ounces, has 3 1/2 servings per container and each serving is 1/2 cup. the price of the ice cream is $4.79.
*March 11, 2009*

**physics help please**

Consider a system in which 3.60 mol of an ideal monatomic gas is expanded at a constant pressure of 101 kPa from an initial volume of 2.15 L to a final volume of 3.87 L. (b) Find the change in temperature for this process. ? K (c) Determine the amount of heat added to or ...
*December 14, 2008*

**Chem: Mole and Avogadros Number**

1.5x10^20
*December 11, 2008*

**physics help 2 please!**

The air inside a hot air balloon has an average temperature of 84.3°C. The outside air has a temperature of 15.3°C. What is the ratio of the density of air in the balloon to the density of air in the surrounding atmosphere? inside / outside = ??
*December 7, 2008*

**physics help pleasee!**

Three moles of oxygen gas (O2) are placed in a portable container with a volume of 0.0037 m3. The temperature of the gas is 330°C. (a) What is the pressure of the gas? ? Pa (b) What is the average kinetic energy of an oxygen molecule? ? J
*December 7, 2008*

**physics 4**!!**

Consider a double-paned window consisting of two panes of glass, each with a thickness of 0.500 cm and an area of 0.880 m2, separated by a layer of air with a thickness of 1.90 cm. The temperature on one side of the window is 0.00°C; the temperature on the other side is 20...
*December 4, 2008*

**physics 3 !!!**

Assuming your skin temperature is 37.2°C and the temperature of your surroundings is 20.5°C, determine the length of time required for you to radiate away the energy gained by eating a 265 Calorie ice cream cone. Let the emmissivity of your skin be 0.915 and its area ...
*December 4, 2008*

**physics 2 ****

A blacksmith drops a 0.60 kg iron horseshoe into a bucket containing 25 kg of water. (a) If the initial temperature of the horseshoe is 600°C, and the initial temperature of the water is 40°C, what is the equilibrium temperature of the system? Assume no heat is ...
*December 4, 2008*

**physics ****

When people sleep, their metabolic rate is about 2.6 10-4 C/(s·kg). How many Calories does a 69 kg person metabolize while sleeping 9.0 hours? ? Cal
*December 4, 2008*

**Physics help 2 please ****

A garden hose is attached to a water faucet on one end and a spray nozzle on the other end. The water faucet is turned on, but the nozzle is turned off so that no water flows through the hose. The hose lies horizontally on the ground, and a stream of water sprays vertically ...
*November 24, 2008*

**Physics help please****

A water pipe having a 2.1 cm inside diameter carries water into the basement of a house at a speed of 0.88 m/s and a pressure of 169 kPa. The pipe tapers to 1.0 cm and rises to the second floor 7.1 m above the input point. (a) What is the speed at the second floor? ? m/s (b) ...
*November 24, 2008*

**physics help pleaseee**

In the figure below, S is a small loudspeaker driven by an audio oscillator with a frequency that is varied from 1000 Hz to 2000 Hz, and D is a cylindrical pipe with two open ends and a length of 55.0 cm. The speed of sound in the air-filled pipe is 344 m/s. (In the figure s ...
*November 16, 2008*

**physics help 4**

An astronaut on a small planet wishes to measure the local value of g by timing pulses traveling down a wire which has a large mass suspended from it. Assume that the wire has a mass of 4.10 g and a length of 1.60 m and that a 3.00 kg mass is suspended from it. A pulse ...
*November 9, 2008*

**Phyiscs help 3**

The height of a tower is measured by attaching a simple pendulum to its ceiling, whose length is barely enough to stay off the floor. The pendulum is let go from a small angle, and takes 13 s to return to the same location it started from. a.) How tall is the tower? ? m If the...
*November 9, 2008*

**physics help 2 please!**

A 4.0 Hz wave with an amplitude of 12 cm and a wavelength of 30.0 cm travels along a stretched horizontal string. (a) How far does a given peak on the wave travel in a time interval of 6.0 s? ? m (b) How far does a knot on the string travel in the same time interval? ? m once ...
*November 9, 2008*

**Physics help please!**

The speed of a deep water wave with a wavelength ë is given approximately by v = (gë/2ð)1/2. Find the speed and frequency of a deep water wave with a wavelength of 5.5 m. ? m/s ? Hz can someone get me started with a formula? I lost my book :(
*November 9, 2008*

**math(Algebra two)**

describe what happens to the graph of y=X^2 in the following situations. a. y is replaced with (y+1) b. x is replaced with(x-5) c.x is replaced with (x+3) d.y is replaced with (y-6) i have no clue how to do this can you please help me?
*November 4, 2008*

**physics help 4 please!!**

Two turtles (each 2 kg) sit on an approximately massless branch in the water. They sit on opposite sides of the branch's center, each 3 m away. The branch (10 m long) is spinning at 2 rad/s about its center (nearly without friction). Now, if both turtles walk to the ends ...
*October 31, 2008*

**physics help 3!! ****

Based on the following data about planet X (which orbits around the Sun): Planet X's distance from Sun = 3.6*1012 m Planet X's radius = 2*106 m Planet X's mass = 8.2*1022 kg a.) Find gx, the size of the acceleration due to gravity on the surface of Planet X. m/s2 b...
*October 31, 2008*

**physics help 2 please!!**

Mass A (7 kg) and mass B (10 kg) sit on the ground, 2 m apart. a.) What is size of the the gravitational force: on A from B? N on B from A? N b.) What is the size of the gravitational force: on A from the Earth? N on B from the Earth? N once again, i am using the wrong ...
*October 31, 2008*

**physics help please!!****

A typical GPS (Global Positioning System) satellite orbits at an altitude of 4.0 107 m. (Astronomical data needed for this problem can be found on the inside back cover of the text.) (a) Find the orbital period of such a satellite. hours (b) Find the orbital speed of such a ...
*October 30, 2008*

**geometry**

you have to sent up a given and then a prove staement and drwa a diagram
*October 26, 2008*

**geometry**

Prove: if th bisector of an angle whose vertex lies on a circle passes through the center of the circle, then it is the prpendiular biector of the se,emt joining the points where the sides of the angle itersect the circle.
*October 26, 2008*

**physics 2, help please**

Two masses (mA= 2 kg, mB= 4 kg) are attached to a (massless) meter stick, at the 0 and 75 cm marks, respectively. c.) Now, if mass B was removed, how much force would need to be exerted at the 100 cm mark in order to keep the meter stick level*? ? N d.) Now, if mass B was ...
*October 23, 2008*

**physics**

A fish takes the bait and pulls on the line with a force of 2.7 N. The fishing reel, which rotates without friction, is a cylinder of radius 0.048 m and mass 0.76 kg. (a) What is the angular acceleration of the fishing reel? ? rad/s2 (b) How much line does the fish pull from ...
*October 23, 2008*

**physics 2...help please**

A wheel on a game show is given an initial angular speed of 1.33 rad/s. It comes to rest after rotating through 3/4 of a turn. (a) Find the average torque exerted on the wheel given that it is a disk of radius 0.76 m and mass 6.4 kg. ? N·m sorry, I'm having ...
*October 22, 2008*

**physics help please**

A torque of 1.15 N·m is applied to a bicycle wheel of radius 36 cm and mass 0.83 kg. Treating the wheel as a hoop, find its angular acceleration. ?rad/s2 I know accel is alpha times the radius...where does torque tie in?
*October 22, 2008*

**PHYSICS 3**

A solid disk (mass = 1 kg, R=0.5 m) is rolling across a table with a translational speed of 9 m/s. a.) What must the angular speed of the disk be? rad/s d.) The disk then rolls up a hill of height 2 m, where the ground again levels out. Find the translational and rotational ...
*October 20, 2008*

**PHYSICS 2**

okay so i have mgh =15.1 and i set it equal to KErot + KE trans? 15.1= 1/2[(2/5 X 2 X .08^2) X (1/2 X 2 X v)^2] that right?
*October 20, 2008*

**PHYSICS 2**

A 2.0 kg cylinder (radius = 0.08 m, length = 0.50 m) is released from rest at the top of a ramp and allowed to roll without slipping. The ramp is 0.77 m high and 5.0 m long. (b) What is its rotational kinetic energy? ? J (c) What is its translational kinetic energy? ? J How do...
*October 20, 2008*

**PHYSICS 1**

thank you so much! i figured it out!
*October 20, 2008*

**PHYSICS 1**

When a pitcher throws a curve ball, the ball is given a fairly rapid spin. A 0.15 kg baseball with a radius of 3.7 cm is thrown with a linear speed of 41 m/s and an angular speed of 37 rad/s. Assume that the ball is a uniform, solid sphere. (b) Calculate how much of its ...
*October 20, 2008*

**physics help 4 please!**

For some reason everytime I try to calculate the KE rotational I do not get the right answer. The translational speed can be used for V, right?
*October 18, 2008*

**physics help 4 please!**

A solid disk (mass = 1 kg, R=0.5 m) is rolling across a table with a translational speed of 9 m/s. a.) What must the angular speed of the disk be? ? rad/s b.) What is the rotational KE of the disk? ? J c.) What is the total KE of the disk? ? J d.) The disk then rolls up a hill...
*October 18, 2008*

**physics help 3 please!!**

A 2.0 kg cylinder (radius = 0.08 m, length = 0.50 m) is released from rest at the top of a ramp and allowed to roll without slipping. The ramp is 0.77 m high and 5.0 m long. (a) When the cylinder reaches the bottom of the ramp, what is its total kinetic energy? (b) What is its...
*October 18, 2008*

**physics help 2!!**

thank you very much, I got the translational, but cant get the rotational. What do I use for v?, do I convert the rad/s?
*October 18, 2008*

**physics help 2!!**

When a pitcher throws a curve ball, the ball is given a fairly rapid spin. A 0.15 kg baseball with a radius of 3.7 cm is thrown with a linear speed of 41 m/s and an angular speed of 37 rad/s. Assume that the ball is a uniform, solid sphere. Calculate how much of its kinetic ...
*October 18, 2008*

**physics help please 1!!**

A 1.27 kg hoop with a radius of 10.0 cm rolls without slipping and has a linear speed of 1.32 m/s. Find the rotational kinetic energy. Find the total kinetic energy of the hoop.
*October 18, 2008*

**PHYSICS**

On a horizontal frictionless table, masses A and B (3 kg, 6 kg) slide to the right and left, respectively. They have speeds of 3 m/s and 1 m/s, respectively. The two masses collide, and bounce off each other. After the collision, they travel in opposite directions at speeds of...
*October 15, 2008*

**physics 3!!****

In a football game, a tackle running at a constant speed of 5 m/s tackles a stationary receiver. The two fly off horizontally at 4 m/s, before they hit the ground and begin to slow down. If the mass of the tackle is 120 kg, a.) What is the mass of the receiver? b.) Calculate ...
*October 12, 2008*

**physics 2!!****

Two ice skaters stand at rest in the center of an ice rink. When they push off against one another the 45 kg skater acquires a speed of 0.71 m/s. If the speed of the other skater is 0.84 m/s, what is this skater's mass?
*October 12, 2008*

**physics!!****

In a typical golf swing, the club is in contact with the ball for about 0.0015 s. If the 45 g ball acquires a speed of 75 m/s, estimate the magnitude of the force exerted by the club on the ball.
*October 12, 2008*

**physics 4...help PLEASE!!**

A skateboarder starts at point A in Figure 8-27 and rises to a height of h = 2.37 m above the top of the ramp at point B. What was the skateboarder's initial speed at point A?
*October 8, 2008*

**physics3..help PLEASE!!**

At the local playground a child on a swing has a speed of 2.14 m/s when the swing is at its lowest point. (a) To what maximum vertical height does the child rise, assuming he sits still and "coasts"? Ignore air resistance. (b) To what maximum vertical height does the...
*October 8, 2008*

**physics 2..help PLEASE!!**

A 63 kg skier encounters a dip in the snow's surface that has a circular cross section with a radius of curvature of 12 m. If the skier's speed at point A in Figure 8-25 is 7.9 m/s, what is the normal force exerted by the snow on the skier at point B? Ignore frictional...
*October 8, 2008*