AP Mechanics

A diver initially moving horizontally with speed v dives off the edge of a vertical cliff and lands in the water a distance d from the base of the cliff. How far from the base of the cliff would the diver have landed if the diver initially had been moving horizontally with speed 2v?

• d
• √2 d
• 2d
• 4d

A ball is thrown and follows the parabolic path shown above. Air friction is negligible. Point Q is the highest point on the path. Points P and R are the same height above the ground. How do the speeds of the ball at the three points compare?

• Vp < Vq < Vr
• Vr < Vq < Vp
• Vq < Vr < Vp
• Vq < Vr = Vp

Which of the following best states the direction of the acceleration of the ball at point P?

• up and right
• right
• down and right
• down

Vectors V1 and V2 shown above have equal magnitudes. The vectors represent the velocities of an object at times t1, and t2, respectively. The average acceleration of the object between time t1 and t2 was

• directed north
• directed west
• directed north of east
• directed north of west

A student is testing the kinematic equations for uniformly accelerated motion by measuring the time it takes for light-weight plastic balls to fall to the floor from a height of 3 m in the lab. The student predicts the time to fallusing g as 9.80 m/s² but finds the measured time to be 35% greater. Which of the following is the most likely cause of the large percent error?

• The acceleration due to gravity is 70% greater than 9.80 m/s² at this location.
• The acceleration due to gravity is 70% less than 9.80 m/s² at this location.
• Air resistance increases the downward acceleration.
• The acceleration of the plastic balls is not uniform.

Starting from rest, object 1 falls freely for 4.0 seconds, and object 2 falls freely for 8.0 seconds. Compared to object 1, object 2 falls:

• half as far
• twice as far
• four times as far
• three times as far

An arrow is aimed horizontally, directly at the center of a target 20 m away. The arrow hits 0.050 m below the center of the target. Neglecting air resistance, what was the initial speed of the arrow?

• 20 m/s
• 40 m/s
• 100 m/s
• 200 m/s

In the absence of air resistance, if an object were to fall freely near the surface of the Moon,

• its acceleration would gradually decrease until the object moves with a terminal velocity.
• the acceleration is constant.
• it will fall with a constant speed.
• the acceleration is zero.

A ball falls straight down through the air under the influence of gravity. There is a retarding force F on the ball with magnitude given by F = bv, where v is the speed of the ball and b is a positive constant. The ball reaches a terminal velocity after a time t. The magnitude of the acceleration at time t/2 is

• increasing
• decreasing
• 9.81 m/s²
• zero

For which of the following motions of an object must the acceleration always be zero?

• any motion in a straight line
• circular motion
• any motion at constant speed
• any object with constant momenutm