Physics - March 2007

A rubber ball with a mass of 200 g is released from rest from a height of 2.0 m. It falls to the floor, bounces, and rebounds. The graph at right depicts the magnitude of the upward normal force that the floor exerts on the ball at various instants in time. The graph only shows the narrow window of time surrounding the interval when the ball was in contact with the floor. e.) What is the impulse on the ball by the earth’s gravitational pull during the same 10 ms? f.) By how much does the ball’s momentum change as a result of this 10-ms period? g.) How high does the ball rebound?

There's also a graph: http://i179.photobucket.com/albums/w298/simplestarlight/49794.jpg

2007-03-26 17:10:02 · 2 answers · asked by Anonymous

A 2400 kg satellite is in a circular orbit around a planet (NOT earth). The satellite travels with a constant speed of 6.67 X 10^3 m/s. The radius of the circular orbit is 8.92 X 10^6 m.

a) What is the acceleration of the satellite?
b) What is the orbital period of the satellite?
c) What is the magnitude of the gravitational force exerted on the satellite by the planet?

2007-03-26 17:02:25 · 3 answers · asked by LesJerLayne 2

A skateboard track has the form of a circular arc with a 4.00 m radius, extending to an angle of 90 degrees relative to the vertical on either side of the lowest point (semicircle). A 57.0-kg skateboarder starts from rest at the top of the circular arc. What is the normal force exerted on the skateboarder at the bottom of the circular arc?

Thanks!

2007-03-26 16:56:25 · 1 answers · asked by 123haha 1

A solid cylinder 30.0 cm in diameter at the top of an incline which is 2.00 meters high is released from rest and rolls to the bottom of the incline without the loss of energy due to friction.
a) Find the linear and angular speeds of the cylinder at the bottom of the incline.
b) After passing over a bump at the end of an incline, the cylinder rolls along now turning at a rate of 1200 rev/min as it traverses a frictionless level surface, a fire ant clinging to the side of the cylinder at a point 0.45 cm from the center (axis of rotation) of the cylinder will experience a centripetal acceleration. What is the centripetal acceleration experienced by the fire ant?

2007-03-26 16:52:36 · 1 answers · asked by LesJerLayne 2

I've got a science fair project coming up. im going to make two greenhouses (because they look cool and will pull in a better grade) and fill one with CO2 to see if it gets hotter in the sun than the other without CO2. my mom says i should just use stupid tubes because they would make it easier and i would get a better result. so what should i do, have fun makeing the greenhouses and maybe not get the most perfect result, or get the clear result with a boring project?

2007-03-26 16:45:42 · 4 answers · asked by Jacob S 1

A rubber ball with a mass of 200 g is released from rest from a height of 2.0 m. It falls to the floor, bounces, and rebounds. The graph at right depicts the magnitude of the upward normal force that the floor exerts on the ball at various instants in time. The graph only shows the narrow window of time surrounding the interval when the ball was in contact with the floor. d) What is the impulse on the ball by the floor during the 10 ms the ball is in contact with the floor? e.) What is the impulse on the ball by the earth’s gravitational pull during the same 10 ms? f.) By how much does the ball’s momentum change as a result of this 10-ms period? g.) How high does the ball rebound?

Link to graph needed:
http://i179.photobucket.com/albums/w298/simplestarlight/49794.jpg

2007-03-26 16:42:46 · 1 answers · asked by Anonymous

2007-03-26 16:25:18 · 13 answers · asked by jeya k 1

2007-03-26 16:18:32 · 5 answers · asked by Victoria A 1

how do you determine the derection of an electric field?

and what is a test charge?

2007-03-26 16:13:43 · 1 answers · asked by Ha!! 2

that is, why do BOTH exist? is there a specific reason why we have them ?

2007-03-26 16:13:08 · 5 answers · asked by lshw 2

9. a) Chlorophyll produces a green solution with organic solvents. The complex chlorophyll molecules must transmit mainly the green wavelength of white light.
i) Which colours must be absorbed?
ii) Which colours should be most suitable for stimulating photosynthesis in indoor plant life?

b) A gardener tries to grow better plants by building a glass house with green glass instead of normal transparent glass. Comment on his experiment.

Please help me and write in sentences with valid points if possible for at least 9.b). I am not sure what to write. I realise that it wouldn't be helpful to use green glass. It could even be detrimental to the health and lifespan of the plants. Normal transparent glass allows the suns rays through normally which help the plant produce photosynthesis using the sunlight, glucose and water etc. A healthy plant has green pigment called chlorophyll. By using green transparent glass...(see I don't know what to say!). Please help me.

2007-03-26 16:08:43 · 2 answers · asked by Anonymous

I want to do a project on the light spectrum, or something similar, but don't know what to do or how to make it interesting
Any Ideas?
Rules: It has to be safe
There's no presentation
no research paper

2007-03-26 15:59:47 · 1 answers · asked by Rosie 2

A 72.0 kg man weighs himself at the north pole and at the equator. It is said that you will weigh more at the north pole. How much more will you weight at the north pole then at the equator?

2007-03-26 15:51:35 · 5 answers · asked by RelientKayers 4

Has anyone done the lab experiment on Two dimensional Kinematics? The experiment was a frictionless table that was inclined and we had to give the puck a push (accelerate it) and record the motion of the puck. However, now we have to analyze the horizontal and vertical motions of a projectile. Any suggstions what I can include in my Introduction, I am not sure what the purpose of this lab is?
Please help.Thanks.

2007-03-26 15:50:36 · 1 answers · asked by Anonymous

2007-03-26 15:49:52 · 1 answers · asked by lana7180 2

Has anyone done the lab experiment on Two dimensional Kinematics? The experiment was a frictionless table that was inclined and we had to give the puck a push (accelerate it) and record the motion of the puck. However, now we have to analyze the horizontal and vertical motions of a projectile. Any suggstions what I can include in my Introduction, I am not sure what the purpose of this lab is?
Please help.Thanks.

2007-03-26 15:48:53 · 2 answers · asked by Anonymous

A 57.7kg astronaut becomes separated from the shuttle, while on a space walk. She finds herself 71.5m away from the shuttle and moving with zero speed relative to the shuttle. She has a 0.983kg camera in her hand and decides to get back to the shuttle by throwing the camera at a speed of 12 m/s in the direction away from the shuttle.
How long will it take for her to reach the shuttle?
Answer in minutes.

2007-03-26 15:42:15 · 1 answers · asked by Laura L 1

Many scientists believe in a multiverse (aka meta-universe, omniverse, alternate reality) which is made up of parallel universes. The theory is that there is an infinite number of realities based on the decisions we make and the lives we touch.

The idea has been examined in hundreds of sci-fi and fantasy novels, television, and movies. "It's a Wonderful Life" is basically a parallel universe in which George was never born. Then, there was "Back to the Future," in which Marty changed his family's destiny by going back in time. Many novels explore "what-if" situations, such as what if Hitler won WW2.

But do they exist, and if so, will it ever be possible to travel from one to another? And if time travel eventually becomes possible, might it be possible for us to completely change the present by going into the past?

See links on http://en.wikipedia.org/wiki/Parallel_universe

2007-03-26 15:25:34 · 7 answers · asked by Anonymous

2007-03-26 15:00:44 · 8 answers · asked by Anonymous

The floors are 3.8 m apart and he climbs to the 5th, 10th and 1st basement floor. I'm not asking for the actual answer but can someone point me in the right way of how to answer the question. I know that Eg = m*g*h but I don't have the mass to start with. I tried using system of equations in math to figure it out but it didn't work. I assume that the mass at each of the floors are the same.

2007-03-26 14:49:12 · 2 answers · asked by Anonymous

A woman whose mass is 54.7 kg stands at the rim of a horizontal turntable which has a moment of inertia of
338 kg m^2 about the axis of rotation and a radius of 2.26 m. The system is initially at rest and the turntable is free to rotate about a frictionless, vertical axle through its center. The woman then starts walking around the rim in a clockwise direction (viewed from above) at a constant speed of 0.873 m/s relative to the ground.

What is its angular speed? Answer in units of rad/s.

How much work does the woman do to set the system into motion? Answer in units of J.

2007-03-26 14:44:14 · 1 answers · asked by lennox lewis 1

On March 21, noon in Seattle the sun would be how high in the sky in degrees?

Tell me how you find the answer, show me the science behind this so I can figure out these questions, thanks.

2007-03-26 14:43:36 · 2 answers · asked by Ryoma Echizen 3

2007-03-26 14:34:20 · 5 answers · asked by Ryoma Echizen 3

there are two parts in this:
1. How is the density of a gas affected by an increase or decrease in temperature?
2. Explain in terms of density and Charles’s Law why heating the air allows a hot-air balloon to float.

help would really be appreciated.

2007-03-26 14:29:04 · 3 answers · asked by Anonymous

Hey everyone... i need help with this question:

In the circuit (see link), the current I1 is 3.0 A while the values of E and R are unknown. What are the currents I2 and I3?

http://img153.imageshack.us/my.php?image=q4gv0.jpg

thanks in advance!

2007-03-26 14:24:23 · 2 answers · asked by Anonymous

The critical angle for a special glass in air is 41.0 degrees. What is the critical angle if the glass is immersed in water?

Please help me with this question.
I don't understand it.

2007-03-26 14:15:11 · 1 answers · asked by vicky p 1

A ray of light strikes a mirror at an angle of 38 degrees to the normal. What is the angle that the reflected angle makes with the normal?

Please help me with this question.
I don't understand it.

2007-03-26 14:05:42 · 4 answers · asked by vicky p 1

If a transistor is basically two diodes and there is a voltage drop Vbe of ca. 0.7V across the base-emitter junction for a fully saturated transistor, then why is there no voltage drop of >= 0.7V across collector-emitter ? Doesn't the collector current have to go across the same base-emitter junction as well ?

2007-03-26 14:04:58 · 4 answers · asked by xfire_2 4

This is one of my physics homework questions. I know that I need to use Poiseuille's Law, but I have no idea how to go about it.
Any suggestions?

1) Angioplasty is a technique in which arteries partially blocked with plaque are dilated to increase blood flow. By what factor must the radius of an artery be increased in order to increase blood flow by a factor of 19?


2)When physicians diagnose arterial blockages, they quote the reduction in flow rate. If the flow rate in an artery has been reduced to 70% of its normal value due to plaque formation, and the average pressure difference has increased by 10%, by what factor has the plaque reduced the radius of the artery?

Thank you very much!

2007-03-26 14:03:10 · 1 answers · asked by ropethiscowgirl 1

Add Historical Background.....I don't understand something...can someone clear this for me?

2007-03-26 14:01:42 · 2 answers · asked by missminie21 1