Question

a) Dr. Liu is learning how to juggle. He tosses a tennis ball (probably bad choice since it is so bouncy) up at 1.6 m/s at a height 1.6 m above the floor and attempts to use the other hand to catch the falling ball. The ball hit the floor at his feet. How long was Dr. Liu's tennis ball in the air (between tossing and landing)? Ignore air drag. He should probably practice tossing his juggling ball at the same height and the same speed before attempting to juggle. Hint: You can set the final position to be zero.

b) In a medieval castle siege reenactment, a castle defender threw down a "stone" (made of soft materials) with all his might, achieving an initial speed of 7 m/s downward. The castle was 7.5 m tall. How long will the attacker have before the "stone" hit the ground? You can assume the final position to be zero. The "stone" has a negligible amount of air drag. Hint: the "stone" has a downward initial velocity.

c) A careless painter dropped a brush (with paint!) from a scaffold outside a building he's supposed to paint. You were just recording a selfie video across the street and caught the falling brush in your video. You used your physics skills to figure out the paintbrush was falling at 6.5 m/s when it was just passing the top of a window that you estimated at 4.6 m above the ground. How long did it take the brush to fall from that height to the ground and make a colorful splash? You can assume the final position to be zero. The paintbrush has a negligible amount of air drag. Hint: the paintbrush has a downward initial velocity at the height you estimated.

Answer 1