Linear Motion
Homework 3: Vertical Motion
1.
If a rock is dropped from a cliff, how fast is it going 1 s later? 2 sec later? 3 sec later?
2.
If a rock is dropped from a cliff, how far did it fall after 1 s? 2 s? 3 s?
3.
If a rock is thrown upward at 50 m/s, how fast is it going 1 s later?
4.
m/s?
If a rock is thrown upward at 50 m/s, how long will it take to reach a velocity of 20
5.
If a rock is thrown upward at 50 m/s, how far above its starting point is it 3 s later?
6.
A penny is dropped from rest from the top of the Sears tower. Considering that the height of
the building is 427 m and ignoring air resistance, find the speed with which the penny strikes the
ground.
7. An astronaut on a distant planet wants to determine the acceleration due to gravity. The
astronaut throws a rock straight up with a velocity of +15 m/s and measures a time of 20.0 s
before the rock returns to his hand. What is the acceleration due to gravity on this planet?
8. From her bedroom, a girl drops a water-filled balloon to the ground, 6.0 m below. If the
balloon is released from rest, how long is it in the air?
9. Calculate the hang time of an athlete that jumps a vertical distance of 0.75 meters.
10. If a salmon swims straight upward in the water fast enough to break through the surface at a
speed of 5 meters per second, how high can it jump above the water?
11. *A wrecking ball is hanging at rest from a crane when the cable suddenly breaks. The time it
takes for the ball to fall halfway to the ground is 1.2 seconds. Find the time it takes for the
ball to fall from rest all the way to the ground.
12. *Two identical pellet guns are fired simultaneously from the edge of a cliff. These guns
impart an initial speed of 30.0 m/s to each pellet. Gun A is fired upward, with the pellet going
upward and then falling back down, eventually hitting the ground beneath the cliff. Gun B is
fired straight downward. In the absence of air resistance, how long after pellet B hits the
ground does pellet A hit the ground?