Physical Science

Chapter 2: Motion

## Gravity and Freefall Practice Problems

g = 9.8 m/s2s = g td = ½ g t2

1. You drop a penny from the top of a tower and it takes 1.85 seconds to hit the ground. Calculate the speed in m/s after 1.10 seconds of freefall, and then calculate the speed in miles/hr.

2. If you drop a watermelon from the top of one of the dorms at UW-Madison, and it takes 3.34 seconds to hit the ground, calculate how tall the building is in meters.

3. You are walking in Paris alongside the Eiffel Tower and suddenly a croissant smacks you on the head and knocks you to the ground. From your handy dandy tourist guidebook you find that the height of the Eiffel Tower is 300.5 m. If you neglect air resistance, calculate how many seconds the croissant dropped before it hit you on the head. (Hint: calculate t2, then find the square root of that to get t)

4. During the latter part of your European vacation, you are hanging out at the beach at the gold coast of Spain. As you are laying in your chaise lounge soaking up the warm Mediterranean sun, large glob of seagull poop hits you in the face. Since you got an “A” in physical science you are able to estimate the impact speed at 98.5 m/s.

(a) Neglecting air resistance, calculate the time it took for the poop to hit you.

(b) calculate how high up the seagull was flying when it pooped.

5. If you were to throw a large log over the edge of the Grand Canyon and it took 5.65 seconds to hit the ground, calculate the speed of the log at impact.

6. Ryan Braun hits a pop-up straight up. The speed of the baseball as it leaves the bat is38.2 m/s.

(a)Calculate how long it took the ball to reach maximum height.

(b)Determine the maximum height the baseball reaches.

(a)Determine the total time the baseball is in the air. Assume the baseball is caught at the same height above the ground as it was hit.

7. A unique type of basketball is played on the planet Gorn. During the game, a

player flies above the basket and drops the ball in from a height of 10 m. If the

ball takes 5 seconds to fall, what is the acceleration due to gravity on planet

Gorn?

8. On the moon, the acceleration due to gravity is only 1.67 m/s/s. If someone on Earth can throw a baseball 24.2 m high, how high could she throw it on the moon?