Student Exploration: Free-Fall Laboratory

Vocabulary: acceleration, air resistance, free fall, instantaneous velocity, terminal velocity,

velocity, vacuum

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1. Suppose you dropped a feather and a hammer at the same time. Which object would hit the

ground first? Hammer

2. Imagine repeating the experiment in an airless tube, or vacuum. Would this change the

result? If so, how? Yes, since there is no air resistance in the vacuum, they would fall at the

same time.

Gizmo Warm-up

The Free-Fall Laboratory Gizmo™ allows you to measure the motion of an

object in free fall. On the CONTROLS pane check that the Shuttlecock is

selected, the Initial height is 3 meters, and the Atmosphere is Air.

1. Click Play ( ) to release the shuttlecock. How long does it take to fall

to the bottom? 0.90 s

2. Select the GRAPH tab. The box labeled h (m) should be checked,

displaying a graph of height vs. time. What does this graph show?

Shows that the shuttlecock is accelerating downwards.

3. Turn on the v (m/s) box to see a graph of velocity vs. time. Velocity is

the speed and direction of the object. Velocity is also referred to as

instantaneous velocity. Because the shuttlecock is falling downward,

its velocity is negative.

Does the velocity stay constant as the object drops? No