Chapter Test A Circular Motion and Gravitation

A heavy bank-vault door is opened by the application of a force of 3.0*10^2 N directed perpendicular to the plane of the door at a distance of 0.80 m from the hinges. What is the torque?

240 N*m

The gravitational force between two masses is 36 N. What is the gravitational force if the distance between them is tripled? (G = 6.673 *10^-11 N•m2/kg2)

4.0 N

A ball is whirled on a string, then the string breaks. What causes the ball to move off in a straight line?

Inertia

Suppose a doorknob is placed at the center of a door. Compared with a door whose knob is located at the edge, what amount of force must be applied to this door to produce the torque exerted on the other door?

Two times as much

When calculating the gravitational force between two extended bodies, you should measure the distance

from the center of each body

The centripetal force on an object in circular motion is

in the same direction as the centripetal acceleration

When an object is moving with uniform circular motion, the object's tangential speed...

is constant

When an astronaut in orbit experiences apparent weightlessness,

the net gravitational force on the astronaut is not balanced by a normal force

How would the speed of Earth's orbit around the sun change if Earth's mass increased by 4 times?

It would increase by a factor of 2

Which of the following is not a valid equation for mechanical advantage?

MA= Wout/Win

If you lift an apple from the ground to some point above the ground, the gravitational potential energy in the system increases. This potential energy is stored in

The gravitational field between the Earth and the apple

The equation for the speed of an object in circular orbit is vt= the square root of G times m/r. What does m represent in the equation?

The mass of the central object

If you cannot exert enough force to loosen a bolt with a wrench, which of the following should you do?

Use a wrench with a longer handle

What kind of simple machine are you using if you pry a nail from a board with the back of a hammer?

a lever