Physics - November 2007

During a tennis serve a racket is given an angular acceleration of magnitude 160rad/s^2. At the top of the serve the racket has an angular speed of 14rad/s. If the distance between the top of the racket and the shoulder is 1.5m find the magnitude of the total acceleration of the top of the racket.

2007-11-27 14:41:51 · 1 answers · asked by Anonymous

A 0.2 kg mass is attached to a spring k = 10 N/m) and hangs vertically near the earth's surface (g = 9.81 m/s2 ). The mass makes contact with a wall as it moves vertically and a constant frictional force of magnitude 5N acts on the mass as it moves.

a) Calculate the amount of work required to pull the spring down by 1 m.
b) Calculate the speed of the mass as it passes through the equilibrium position after being pulled down by 1 m.

2007-11-27 14:39:39 · 1 answers · asked by korr 2

i asked this in chemistry and got no answer, so ill ask it here.

according to my chemistry teacher 2 electrons in an orbital have to have opposite spins, so one is +1/2, the other is -1/2. but electrons are leptons, which all have -1/2 spin. so how does the spin of an electron change if its supposed to be -1/2.

2007-11-27 14:39:31 · 1 answers · asked by Anonymous

An auto race is hed on a track. A car completes one lap in a time of 18.9s with an average tangential speed of 42.6m/s. Find the average angular speed and the radius of the track.

2007-11-27 14:33:58 · 1 answers · asked by Anonymous

a screen containing 2 slits 0.100 mm apart is 1.2 m from th viewing screen. LIght of wavelength is 400 nm *violet light* falls on the slits from a distant source.
a. approx how far apart will the interference fringes be on the screen?
b. if instead wavelength= 700 nm *red lights* how far apart will interfernece fringes be?
c. describe what would be seen if white light was used ?

please help test tomorrow

2007-11-27 14:32:36 · 2 answers · asked by Anonymous

According to Einstein, the speed of light can "neither be reached nor exceeded by any real body."

Why are photons so special that they get to go that fast?

2007-11-27 14:32:20 · 4 answers · asked by John K 3

A superball with a mass of 47.3g is dropped from a height of 3.6m. it rebounds to a height of 3.2m.?
The acceleration of gravity is 9.8m/s/s. What is the change in its linear momentum during the collision with the floor? Answer in units of kg m/s.

2007-11-27 14:26:54 · 1 answers · asked by njbadboy4life2005 3

Two particles, of masses m and 3m, are moving toward each other along the x-axis with the same initial speeds of 7.27 m/s. Mass m is travelling to the left, and mass 3m is traveling to the right. They undergo a head-on elastic collision and each rebounds along the same line as it approached.

Find the final speed of the heavier particle. answer in m/s

i have no idea what to do.

2007-11-27 14:24:00 · 1 answers · asked by njbadboy4life2005 3

A ball player hits a home run, and the baseball just clears a wall 8.00 m high located 132.8m from the home plate. The ball is hit at an angle of 38.8 degrees to the horizontal, and air resistance is negligible. Assume the ball is hit at a height of 1.1 m above the ground. The acceleration of gravity is 9.8 m/s^2.

What is the initial speed of the ball in units of m/s?

How much time does it take for the ball to reach the wall in units of seconds?

Find the speed of the ball when it reaches the wall. Answer in units of m/s

2007-11-27 14:17:28 · 1 answers · asked by Anonymous

My son is a grad student in analytical chemistry at the U of Minn-Twin Cities and he recently published his first article in the "Analytical Chemistry Journal." They accepted the article exactly the way he wrote it! NO revisions, NO editing, NO changes! It's in this month's volume. No one, including myself, has ever heard of that! Have you?

He's been working on tips for STM and came up with something better and cheaper than any one else before.

No correct answers for this. Just bragging about my first born to people who might know something about STM. Sorry if you don't approve the use of this medium to do that. I'm just so proud!

2007-11-27 14:13:54 · 2 answers · asked by ThisIsIt! 7

A plane drops a hamper of medical supplies from a height of 4610 m during a practice run over the ocean. The plane's horizontal velocity was 117 m/s at the instant the hamper was dropped.

The acceleration of gravity is 9.8 m/s^2. What is the magnitude of the overall velocity of the hamper at the instant it strikes the surface of the ocean? Answer in units of m/s.

2007-11-27 14:05:35 · 1 answers · asked by Anonymous

A 0.590 kg wood block is firmly attached to a very light horizontal spring (k = 200 N/m) as shown in Fig. 6-40. It is noted that the block-spring system, when compressed 5.0 cm and released, stretches out 2.3 cm beyond the equilibrium position before stopping and turning back. What is the coefficient of kinetic friction between the block and the table?

2007-11-27 13:49:35 · 1 answers · asked by lcbby 1

How much heat is required to raise the body temperature of a 60-kg woman from 21.9°C to 57.3°C?

2007-11-27 13:46:51 · 1 answers · asked by Bob P 1

The illumination of an object by a light source is directly proportional to the strength of the source and inversely proportional to the square of the distance from the source. If two light sources, one four times as strong as the other, are placed 18 m apart, how far away from the stronger light source should an object be placed on the line between the two sources so as to receive the least illumination?

plz help

2007-11-27 13:34:06 · 2 answers · asked by JK 1

A 0.590 kg wood block is firmly attached to a very light horizontal spring (k = 200 N/m) as shown in Fig. 6-40. It is noted that the block-spring system, when compressed 5.0 cm and released, stretches out 2.3 cm beyond the equilibrium position before stopping and turning back. What is the coefficient of kinetic friction between the block and the table?

2007-11-27 13:32:09 · 1 answers · asked by lcbby 1

2007-11-27 13:27:18 · 1 answers · asked by lindsay d 1

Trying to figure out how to correlate speed in mph with a free fall in feet.

2007-11-27 13:25:14 · 1 answers · asked by Anonymous

It looks like its burnt, is it from radiation? I also notice it when I move my TV away from the wall, there will be black markings where the TV was.

2007-11-27 13:22:22 · 2 answers · asked by poor_old_lu17 1

i have no science capabilities whatsoever!
here are the questions:

1-how does the strong nuclear force affect an atoms electrons?
2-why do fission chain reactions of uranium-235 not occur in underground uranium deposits?
3-does fermium-257 undergo nuclear decay?

thanks alot!

2007-11-27 12:55:40 · 5 answers · asked by hannamoor 2

A 24 kg crate initially at rest on a horizontal floor requires a 75 Newtons horizontal force to set it in motion. The coefficient of static friction between the crate and the floor is 0.32.
Once the crate is in motion, a horizontal force of 53 Newtons keeps the crate moving with a constant velocity. What is the coefficient of kinetic friction between the crate and floor??

PLEASE HELP ME!!!! THANKS IN ADVANCE!!!!

2007-11-27 12:55:39 · 1 answers · asked by Anonymous

On earth, the tides are in part determined by the Moon. So what happens when a body full of water attempts to walk on the moon?

2007-11-27 12:52:16 · 2 answers · asked by Roy Nicolas 5

2007-11-27 12:43:53 · 1 answers · asked by mae 1

A clarinet behaves like a tube closed at one
end.
The velocity of sound is 344 m/s :
If its length is 1.9 m, what is its fundamen-
tal frequency? Answer in units of H

2007-11-27 12:36:56 · 3 answers · asked by yoyoyoyoyoyo 2

A 55 kg trampoline artist jumps vertically upward from the top of a platform with a speed of 5.0 m/s. (Ignore small changes in gravitational potential energy.)


(a) How fast is he going as he lands on the trampoline, 3.0 m below?
___ m/s
(b) If the trampoline behaves like a spring of spring constant 5.2 104 N/m, how far does he depress it?
___m





A 0.590 kg wood block is firmly attached to a very light horizontal spring (k = 200 N/m) as shown in Fig. 6-40. It is noted that the block-spring system, when compressed 5.0 cm and released, stretches out 2.3 cm beyond the equilibrium position before stopping and turning back. What is the coefficient of kinetic friction between the block and the table?





can anyone do any of that?!?!?

2007-11-27 12:26:53 · 1 answers · asked by lcbby 1

2007-11-27 11:46:45 · 1 answers · asked by Anonymous

1. A clerk moves a box down a horizontal aisle by pulling on straps attached to the box. The horizontal force is 250 newtons. The box is 35 kg. What is the coefficiant of kinetic friction?


2. What is the acceleration of a pillow that is being pulled 5 newtons in a 37 degree angle. The mass of the pillow is 1.0 kg.

3. what are the x and y componets of a 509 kg pumpkin inclined on 30 degree angle. (Assume the pumpkin is at rest)

2007-11-27 11:37:33 · 1 answers · asked by G. MoneY 2

4 science homework......thnx.....

2007-11-27 11:33:41 · 4 answers · asked by Anonymous

A 202-kg crate is pushed horizontally with a force of 709 N. If the coefficient of friction is 0.20, what is the acceleration of the crate?

2007-11-27 11:27:51 · 1 answers · asked by Anonymous

A car that's 2460.0-kg is driving at a constant speed of 11.0 m/s along an icy, but straight and level road. While approaching a traffic light, it turns red. Slam on the brakes, wheels lock, tires begin skidding, and the car slides to a halt in a distance of 25.0 m. What is the coefficient of sliding friction (µ) between your tires and the icy roadbed?

2007-11-27 11:02:06 · 1 answers · asked by Anonymous

Hopping into your car, you floor it and accelerate at 9.1 m/s^2 without spinning the tires. Determine the minimum coefficient of static friction between the tires and the road needed to make this possible.

Please show/explain all work clearly please!

2007-11-27 10:35:13 · 3 answers · asked by nirmal 1