Physics Quiz 05 (Ch 7)

Centripetal acceleration must involve a change in

• an object’s tangential speed.

• an object’s velocity.

• both an object’s speed and direction.

• the radius of an object’s circular motion.

What is the speed of an object in circular motion called?

• circular speed

• centripetal speed

• tangential speed

• inertial speed

Which of the following is the correct equation for centripetal acceleration?

• $a_c=\frac{v_t^2}{r}$

• $a_c=\frac{v_t}{r}$

• $a_c=\frac{mv_t^2}{r}$

• $a_c=\frac{\left(v_{t,f}-v_{t,i}\right)}{\Delta t}$

What term describes a force that causes an object to move in a circular path?

• circular force

• centripetal acceleration

• centripetal force

• centrifugal force

Centripetal force can be calculated from centripetal acceleration by

• dividing by the mass.

• multiplying by the mass.

• squaring the acceleration and dividing by the radius.

• squaring the acceleration, multiplying by the mass, and dividing by the radius.

What is the centripetal force that holds planets in orbit?

• inertia

• gravitational force

• planetary force

• Kepler’s force

The force that Earth exerts on the moon

• is greater than the force the moon exerts on Earth.

• is less than the force the moon exerts on Earth.

• is equal in magnitude to the force the moon exerts on Earth.

• causes tides.

How does the gravitational force between two objects change if the distance between the objects doubles?

• The force decreases by a factor of 4.

• The force decreases by a factor of 2.

• The force increases by a factor of 2.

• The force increases by a factor of 4.

What does G stand for?

• free-fall acceleration

• gravitational field strength

• the constant of universal gravitation

• gravitational force

Evidence confirms that gravitational mass

• depends on gravitational field strength.

• varies with location.

• depends on free-fall acceleration.

• equals inertial mass.