physics exam 3 conceptual

A disk is free to rotate about an axis. A force applied at a distance d from the axis causes an angular acceleration . What angular acceleration is produced if the same force is applied a distance 2d from the axis? - theta -2theta -theta/2 -4theta -theta/4

-4theta

If the temperature and pressure of an ideal gas are both doubled, the volume will be -unchanged. -doubled. -cut in half. -multiplied by four. -divided by four.

-unchanged.

Two points, A and B, are on a disk that rotates about an axis. Point A is closer to the axis than point B. Which of the following is not true? 1) Point B has the greater speed. 2) Point A has the lesser centripetal acceleration. 3) Points A and B have the same angular acceleration. 4) Point B has the greater angular speed. 5) Point A has the lesser tangential acceleration.

5) Point A has the lesser tangential acceleration.

The angular acceleration is directly proportional to: ? The angular acceleration is inversely proportional to t

:the net torque :moment of inertia of the object

An ice skater performs a pirouette (a fast spin) by pulling in his outstretched arms close to his body. What happens to his angular momentum about the axis of rotation? A) It does not change. B) It changes, but it is impossible to tell which way. C) It increases. D) It decreases.

A) It does not change.

Why Do Lakes Freeze on the Top First?

As air cools, the water at the top contracts and becomes more dense than the water below ⇒ cooler water sinks T < 4C: further lowering of the air temperature causes an expansion of the water on top ⇒ cooler water stays on top, where it freezes.

If a constant net torque is applied to an object, that object will: A) having an increasing moment of inertia. B) rotate with constant angular velocity. C) rotate with constant angular acceleration. D) rotate with constant linear velocity. E) having a decreasing moment of inertia.

C) rotate with constant angular acceleration.

If the Earth had four times its present mass, what would be its new period of revolution around the sun, compared to its present orbital period? A) one-fourth as much B) two times as much C) the same D) one-half as much E) four times as much

C) the same

True or False At constant volume, the absolute pressure of a gas is inversely proportional to the absolute temperature.

False

True or False: When a rigid body rotates about a fixed axis all the points in the body have the same tangential speed.

False

ideal gas law

P1V1/T1 = P1V1/T1

For angular momentum to be conserved, the net torque must be zero.

True

True or False In kinetic theory, a gas is modeled as being made up of a large number of molecules which bounce from the walls of the container.

True

True or False: The constant K in Kepler's Third Law is the same for all the planets in our solar system, but is different for planetary systems orbiting other stars.

True

When a rigid body rotates about a fixed axis all the points in the body have the same angular acceleration.

True

Charles's law

V1/T1 = V2/T2

Atoms have high amplitude of vibration at....

high t

When an ideal gas increases in volume at constant pressure, the average kinetic energy of the gas molecules...

increases

Atoms have small amplitude of vibration at....

low T.

Boyle's law

p1V1 = p2V2

revolutions --> radians

revolutions x 2pi = radians

Torque is a ...

vector quantity.