1. A rock is dropped from rest at the top of a cliff and falls 125 m before hitting the ground.
a. How long does the rock take to hit the ground?
b. What is the rock’s velocity when it hits?
2. A springbok is an antelope found in southern Africa that gets its name from its remarkable jumping
ability. When the springbok is started, it will leap straight up into the air – a maneuver called a “pronk”.
A springbok goes into a crouch to perform a pronk. It then extends its legs forcefully, accelerating at 30
m/s2 for 0.60 m as its legs straighten. Legs fully extended, it leaves the ground and rises into the air.
a. How fast is the springbok moving when its feet leave the ground?
b. How long will it take the springbok to reach its maximum height?
c. How long will it take the springbok to reach the maximum height?
3. Ball bearings can be made by letting spherical drops of molten metal fall inside a tall tower – called a
shot tower – and solidify as they fall.
a. If a bearing needs 5.0 seconds to solidify enough for impact, how high must the tower be?
b. What is the bearing’s impact velocity?
4. A ball is thrown straight up with an initial velocity of 25 m/s.
a. How high will it go?
b. How long will it be in the air?
c. What will the velocity be when the ball hits the ground?
5. Student A at the top of a building throws a rock upward at vo at the same time Student B throws a rock
towards the ground at – vo.
a. Which rock will have the greatest acceleration?
b. Which rock will reach the ground first?
c. Which rock will have the greatest velocity when it hits the ground?
6. A ball is thrown upward from the ground and takes 8.2 seconds to hit the ground.
a. How fast was the ball thrown?
b. How high did it go?
7. A ball is thrown upward from a 25 m building with an initial velocity of 35 m/s. How long will it take to
hit the ground?