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Physics Chapter 7 Test

Terms in this set (17)

When an object is moving with uniform circular motion, the object's tangential speed
is constant.
The centripetal force on an object in circular motion is
in the same direction as the centripetal acceleration.
A ball is whirled on a string, then the string breaks. What causes the ball to move off in a straight line?
inertia.
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 Earth and the apple
When calculating the gravitational force between two extended bodies, you should measure the distance
from the center of each body.
Newton's law of universal gravitation
can be used to derive Kepler's third law of planetary motion.
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.
When an astronaut in orbit experiences apparent weightlessness,
the net gravitational force on the astronaut is not balanced by a normal force.
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.
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
What kind of simple machine are you using if you pry a nail from a board with the back of a hammer
a lever.
Centripetal acceleration must involve a change in
an object's velocity.
What is the speed of an object in circular motion called?
tangential speed
What term describes a force that causes an object to move in a circular path?
centripetal force
A centripetal force acts
perpendicular to tangential speed but in the same plan.
Centripetal force can be calculated from centripetal acceleration by
multiplying by the mass.
Which of the following is due to inertia?
A ball whirled in a circular motion will move off in a straight line if the string breaks.
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