Physics - November 2007

A 85.0 cm diameter wheel accelerates uniformly from 220 rpm to 390 rpm in 7.0 s. How far will a point on the edge of the wheel have traveled in this time?

2007-11-14 14:25:41 · 2 answers · asked by Bob J 1

A ball is thrown horizontally out the window of a building with a velocity of 8.0m/s from a height of 200m. How far from the base of the building will the ball land? (Use g=10m/s^2)

A. 115 m
B. 51 m
C. 90 m
D. 180 m
E. 60 m

2007-11-14 14:25:18 · 1 answers · asked by Anonymous

An electron and a positron each have a mass of 9.11x10^-31 kg. They collide and both vanish, with only electromagnetic radiation appearing after the collision. If each particle is moving at a speed of 0.10c relative to the laboratory before the collision, determine the energy of the electromagnetic radiation.
(answer is in Joules)

2007-11-14 14:24:57 · 2 answers · asked by allyn_03 2

A bicycle has wheels 0.94 m in diameter. The bicyclist accelerates from rest with constant accleration to 7.52 m/s in 5.57 seconds.

What is the angular acceleration of the wheels?


Then you are given

α= 1.47 rad/s/s and t=2.41 s.

How many revolutions does it go through?

2007-11-14 14:22:33 · 1 answers · asked by Anonymous

DId the concept of higher physical dimensions exist in Maxwell's time? Has anyone explored the ramifications of modern GU theories on EM propogation or has it been somehow established that it is bound to ordinary 3D spacetime? What would be a test to determine if it was or not?

2007-11-14 13:59:16 · 1 answers · asked by AmigaJoe 3

True science states that in order for a theory to become a fact, it must be reproduced in a lad successfully many times over. Since noone was there in the beginning to record the exact conditions, any experiments must be based on unproven speculation. Therefore, the theory of evolution, is a faith based religion ( Humanism ), just as the theory of creation is. What is your response to this statment, and please show your reasons.

2007-11-14 13:44:03 · 11 answers · asked by Michael G 1

A physics professor is pushed up a ramp inclined upward at an angle theta above the horizontal as he sits in his desk chair that slides on frictionless rollers. The combined mass of the professor and chair is m. He is pushed a distance x along the incline by a group of students who together exert a constant horizontal force of F. The professor's speed at the bottom of the ramp is v.

Problem:
Use the work-energy theorem to find his speed at the top of the ramp.

I've tried this problem over 7 times, please help

2007-11-14 13:40:09 · 1 answers · asked by Anonymous

2007-11-14 13:32:04 · 7 answers · asked by Anonymous

two 200 kg lead spheres are suspended from 200 m long massless cables.the tops of the cables have been carefully anchored exactly 1 m apart.what is the distance between the centers of two spheres?

i tried to use gravitional forces to calculate the distance,but here we have cables.
please help me get this question.
thanks

2007-11-14 13:25:19 · 1 answers · asked by Anonymous

Need help with this problem:
Trailing by two points and with only 2.0 seconds remaining in a basketball game, Amy takes a jump shot at an angle of 60 degrees with the horizontal giving the ball a velocity of 10 m/s. The ball is released at the height of the basket 3.05 m above the floor. She makes the shot.
A. How much time is left in the game when the basket is made?
B. Shots made outside the semicircle of 6.02 m radius is worth 3 points. Did amy make a 2 or a 3 point shot?

2007-11-14 13:14:39 · 1 answers · asked by suzanne d 2

What is the smallest part of a centimeter that can be read or estimated with your micrometer caliper? This represents the sensitivity of the micrometer, for the sensitivity of a measuring instrument is the value of the smallest quantity that can be read or estimated with it.

2007-11-14 13:10:02 · 1 answers · asked by Anonymous

What's something commonplace that people do that demonstrates all of Newton's Laws? I can't think of any! Help!!!

2007-11-14 13:07:49 · 1 answers · asked by Olivia R 1

2007-11-14 13:07:33 · 1 answers · asked by Kevin J 1

A child attempts to drink water through a 115 cm long straw, but finds that the water rises only 50 cm. By how much has the child reduced the pressure in her mouth below atmospheric pressure?

2007-11-14 13:04:55 · 1 answers · asked by wil 1

Why are several observations taken for each measurement?

2007-11-14 13:03:55 · 1 answers · asked by Anonymous

Use the Equipartition Theorem to help answer this.

2007-11-14 12:52:09 · 10 answers · asked by laudie3a 2

Don't calculate it here, merely explain what you need to do in order to calculate it. Give the strategy, not the result.

2007-11-14 12:50:33 · 2 answers · asked by laudie3a 2

Two horizontal forces, 221 N and 186 N, are exerted in opposite directions on a crate. What is the net horizontal force on the create? Be sure to indicate the direction of the net force. (Assume that the 221 N force is in the positive direction.)

2007-11-14 12:14:24 · 4 answers · asked by Anonymous

A speed boat capable of 30km/h is to cross a river to a point directly opposite its starting point. The river flows at 4km/h. At what angle to the bank must the boat be steered? How long will it take if the river is 150m wide?

2007-11-14 12:11:52 · 2 answers · asked by firemama 1

One tied to a tree and the other to a horse. No problem. Compare the tension he experiences in two other situations (horse and horse, and two horses and the tree).

2007-11-14 12:11:31 · 2 answers · asked by camila_faria33 1

2007-11-14 12:07:11 · 2 answers · asked by ynkilc 1

Okay I need help with this problem:

1. You carry two heavy suitcases up a flight of stairs. Will you do more work on the bags if you carry them up one at a time? Explain why or why not.

If you're wondering. We're currently working on the unit of "Work, Power, and Machines"

2007-11-14 12:07:10 · 2 answers · asked by Anonymous

1. Can the kinetic energy of an object be negative?


2. In a collision between two cars, one car left skid marks twice the length of those left by the other car. A bystander who viewed the collision claims that the cars applied their brakes at the same time. What conclusions can you draw?


3. Two identical objects move with speeds of 5 m/s and 20m/s, what is the ratio of their kinetic energies?

2007-11-14 12:03:10 · 5 answers · asked by johnnyboy 2

A man drops a rock off a cliff 4.3 sec. later it hits the ground how far did it fall in meters the formula is Distance =1/2 x (acceleration) x ( time)2

2007-11-14 12:00:11 · 1 answers · asked by awesome 2

11.03 meters per second to miles per hour. can you show me the work please?

2007-11-14 11:59:34 · 1 answers · asked by Anonymous

Three 7.31 kg masses are at the corners of an equilateral triangle and located in space far from any other masses. If the sides of the triangle are 1.20 m long, calculate the magnitude of the net force exerted on each of the three masses.

2007-11-14 11:59:13 · 1 answers · asked by Anonymous

2007-11-14 11:49:37 · 7 answers · asked by ynkilc 1

2007-11-14 11:37:15 · 2 answers · asked by Shawn 1

2007-11-14 11:22:04 · 1 answers · asked by Shawn 1

2007-11-14 11:15:07 · 5 answers · asked by Anonymous