Physics exam 4

Which of the following statements are true? A) A geosynchronous satellite has a period of approximately 28 days. B) A satellite's velocity and orbital radius are independent of each other. C) The launch speed of a satellite determines the shape of its orbit around Earth. D) A satellite's motion is independent of its mass.

C and D

Forces that do work such that a potential energy can be defined are called

Conservative forces

Power is the rate at which __ is transformed

Energy

A stone is held at a height h above the ground. A second stone with four times the mass of the first one is held at the same height. The gravitational potential energy of the second stone compared to that of the first stone is

Four times as much

Newtons law of universal gravitation

Fug= GMm/r^2

If human beings ever travel to a planet whose mass and radius are both twice that of the earth, their weight on that planet will be

Half of their weight on earth

SI unit for energy is

Joule (J)

Definition of Kinetic Energy

KE=1/2mv^2

Ideal pulley

Massless, frictionless, and string does not slip

potential energy depends on

Position

If the parallel force is in the same direction as the displacement, then the work is __, and KINETIC ENERGY __.

Positive, increases

Work is the

Product of the component of force in the direction of the displacement and the magnitude of the displacement (s)

Two objects attract each other gravitationally. If the distance between their centers decreases by a factor of 2, how does the gravitational force between them change?

The gravitational force increases by a factor of 4.

If the net work done on an object is zero, what can you determine about the object's kinetic energy?

The object's kinetic energy remains the same.

The work done by a non conservative force depend on

The path taken

A graph depicts force versus position. What represents the work done by the force over the given displacement?

The work done is equal to the area under the curve.

Why does a satellite in a circular orbit travel at a constant speed?

There is no component of force acting along the direction of motion of the satellite.

Definition of elastic potential energy

Uel= 1/2*kx^2

Definition of gravitational potential energy

Ug= mgy

Definition of universal gravitational potential energy

Uug= -GmM/r

The SI unit of power is

Watt

Power is the rate at which _____ is done.

Work

A ball is thrown straight upward. How does the sign of the work done by gravity while the ball is traveling upward compare with the sign of the work done by gravity while the ball is traveling downward?

Work done by gravity is negative while the ball is traveling upward and positive while the ball is traveling downward.

Work done by a conservative force is

independent of the path

Work is a _____ quantity, but can be _ or _.

scalar, positive or negative

If the net work done on an object is positive, what can you conclude about the object's motion?

the object is speeding up