Physics Chapter 7

How does the use of a machine alter the work done on the object?

It multiplies the force being used

Is there an outward force in circular motion? explain

No because there is no interaction between the objects in that direction

Two horses are side by side on a carousel. Which has a greater tangential speed - the one closer to the center or the one farther from the center? Explain

The farther horse because it has a larger radius and a farther distance to travel

Where should a force be applied on a lever arm to produce the most torque? A. closest to the axis of rotation B. farthest from the axis of rotation C. in the middle of the lever arm D. it doesn't matter where the force is applied

farthest from the axis of rotation

When calculating the gravitational force between two extended bodies, you should measure the distance A. from the closest points on each body B. from the most distant part on each body C. from the center of each body D. from the closest point on one body to the center of the other body

from the center of each body

The centripetal force on an object in circular motion is A. perpendicular to the plane of the object's motion B. in the plane of the object's motion and perpendicular to the tangential speed C. in the plane of the object's motion and in the same direction the tangential speed D. in the plane of the object's motion and in the direction opposite the tangential speed

in the plane of the object's motion and perpendicular to the tangential speed

The centripetal force on an object in circular motion is A. in the same direction as the tangential speed B. in the direction opposite the tangential speed C. in the same direction as the centripetal acceleration D. in the direction opposite the centripetal acceleration

in the same direction as the centripetal acceleration

When a car makes a sharp left turn, what causes the passengers to move toward the right side of the car? A. centripetal acceleration B. centripetal force C. centrifugal force D. inertia

inertia

When an object is moving with uniform circular motion, the centripetal acceleration of the object A. is circular B. is perpendicular to the plane of motion C. is zero D. is directed towards the center of motion

is directed towards the center of motion

Why does an astronaut weigh less on the moon than on earth? A. the astronaut has less mass on the moon B. the astronaut is farther from Earth's center when he or she is on the moon C. the gravitational field strength is less on the moon's surface than on Earth's surface D. the astronaut is continually in free fall because the moon orbits Earth

the gravitational field strength is less on the moon's surface than on Earth's surface

Explain how an object moving at a constant speed can have a nonzero acceleration

the object is moving in a circle

What provides the centripetal force for a ball whirled on a string?

the string

what provides the centripetal force for a car driving on a circular path?

the tires of the car in contact with the track

Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis? A. axis of rotation B. lever arm C. tangential force D. torque

torque

If you cannot exert enough force to loosen a bolt with a wrench, which of the following should you do? A. use a wrench with a longer handle B. tie a rope to the end of the wrench and pull the rope C. use a wrench with a shorter handle D. you exert a force on the wrench closer to the bolt

use a wrench with a longer handle

What is the term for the net force directed towards the center of an object's circular path? A. circular force B. centrifugal force C. centripetal force D. orbital force

centripetal force

Which of the following can be a centripetal force? A. friction B. gravity C. tension D. all of the above

all of the above

If you want to open a swinging door with the least amount of force, where should you push on the door? A. close to the hinges B. in the middle C. as far from the hinges as possible D. it does not matter where you push

as far from the hinges as possible