Free Fall Concepts

When we say that light objects and heavy objects fall at the same rate, what assumption are we making?

• They have the same shape.

• They are falling in a vacuum

• They are made of the same material.

• They have the same size.

The moon is a nice place to study free-fall because it has no atmosphere. If an astronaut on the moon simultaneously drops a hammer and a feather from the same height, which one hits the ground first?

• the hammer

• the feather

• They hit at the same time.

• They don't fall.

The motion of a block sliding down a frictionless ramp can be described as motion with

• a constant speed.

• a constant acceleration greater than 10 m/s/s.

• a constant acceleration less than 10 m/s/s.

• a constant speed that depends on the steepness of the ramp.

If a ball is dropped from rest, it will fall 5 m during the first second. How far will it fall during the second second?

• 5 m

• 10 m

• 15 m

• 20 m

A ball with a mass of 0.5 kg is thrown vertically upward with a speed of 15 m/s. What are its speed and direction two seconds later?

• 10 m/s upward

• 5 m/s upward

• zero

• 5 m/s downward

If we use plus and minus signs to indicate the directions of velocity and acceleration, in which of the following situations does the object speed up?

• positive velocity and negative acceleration

• negative velocity and positive acceleration

• positive velocity and zero acceleration

• negative velocity and negative acceleration

Suppose an object is in free fall. Each second the object falls

• the same distance as in the second before.

• a larger distance than in the second before.

• with the same instantaneous speed.

• with the same average speed.

Consider drops of water leaking from a water faucet. As the drops fall they

• remain at a relatively fixed distance from each other.

• get farther apart.

• get closer together

A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

• in the direction of motion.

• opposite its velocity.

• directed downward.

• directed upward.

The hang time (time one's feet are off the ground in a jump) for most athletes is

• less than 1 second.

• considerably more than 1 second.

• about 1 second.

• slightly more than 1 second.