An object that's moving with constant speed travels once around a circular path. Which of the following is/are true concerning this motion?

I. The displacement is zero.
II. The average speed is zero.
III. The acceleration is zero.

A rock is thrown off a 30 m cliff at a 45° angle above the horizontal. When the rock is 15 m above the ground, what is its acceleration?

A baseball is thrown straight upward. What is the ball's acceleration at its highest point?

How long would it take a car, starting from rest and accelerating uniformly in a straight line at 5 m/s^2, to cover a distance of 200 m?

A rock is dropped off a cliff and strikes the ground with an impact speed of 30 m/s. How high was the cliff?

A stone is thrown horizontally with an initial speed of 10 m/s from a bridge. If air resistance could be ignored, how long would it take the stone to strike the water 80 m below the bridge?

A soccer ball, at rest on the ground, is kicked with an initial velocity of 10 m/s at a launch angle of 30°. Calculate its total flight time, assuming that air resistance is negligible.

A stone is thrown horizontally with an initial speed of 30 m/s from a bridge. Find the stone's total speed when it enters the water 4 seconds later. (Ignore air resistance.)

Which one of the following statements is true concerning the motion of an ideal projectile launched at an angle of 45° to the horizontal?

The position of an object moving in a straight line is given by the equation x = (3t^3+7t+5) m, where t is in seconds. What is the object's acceleration at time t = 5 seconds?