Name: __________________________
Free-Fall Worksheet A
1. A rock is thrown straight upward with an initial velocity of 30 m/s as shown in the diagram below.
a. On the diagram, label the velocity of the rock at each second.
b. Plot its velocity vs. time on the graph below.
40
30
20
10
velocity
(m/s)
0
-10
-20
-30
-40
0
1
2
3
4
5
6
7
8
time
(s)
c. Calculate its displacement after 7 seconds using the graph.
d. What is its displacement after 6 s?
2. A different rock is thrown with an initial upward speed of 20 m/s and
the graph shown to the right is obtained.
a. What is the acceleration of the rock?
40
b. Is the rock being thrown on Earth? _____
c. What is the speed of the rock when it
reaches its highest point? ____________
d. What is the acceleration of the rock when
it is at its highest point? (careful – think
slope) ____________
e. What is the displacement of the rock
when it reaches its highest point?
30
20
10
velocity
(m/s)
0
-10
-20
-30
-40
0
2
4
6
8
time
(s)
10
12
14
16
3. (Walker 2.70) On a hot summer day several swimmers decide to jump into a river. They step off the
bridge and strike the water 1.5 s later. Ignore air resistance.
a. What is the height of the bridge?
b. How fast are the swimmers moving when they strike the water?
4. Assume that the center of the Tacoma Narrows Bridge roadway is about 60 m above the water. Ignore air
resistance.
a. How long would it take for a rock dropped from the bridge to reach the water?
b. How fast would the rock be moving just before striking the water?