Question

a. An attacker at the base of a castle wall 3.65 m high throws a rock straight up with speed

7.40 m/s from a height of 1.55 m above the ground. Will the rock reach the top of the wall?

If so, how fast is it moving when it reaches the top. If not, what initial speed must it have

to reach the top?

b. To defend the castle, a rock is thrown downwards from the top of the wall with an initial

speed of 7.40 m/s. What is this rock’s speed as it passes the height of 1.55 m from the

ground?

c. Does the change in speed of the downward moving rock agree with the magnitude of the

speed change of the rock moving upward between the same elevations? Explain physically

why it does or does not agree. Astronaut David Scott dropped a hammer and a feather at the same time on the Moon,

from a height of 1.20 m and observed them hit the lunar soil at the same time. The surface

gravity of the Moon gives a constant acceleration of 1.62 m/s squared

d. How long did it take for the objects to hit the surface of the Moon after their release?

e. What was the speed of the objects as they hit the surface of the Moon?

Answer 1