There is no air resistance in any of these problems.
1. Consider a ball kicked horizontally off a rooftop at 20 m/s. The building is 40 m above the ground.
a. How long does it take the ball to reach the ground?
b. How far from the base of the building does the ball land?
2. You are trying to cross a river that is 100 m wide. Your boat normally travels at 15 m/s in still water and you head directly across the river. However, the current of the river is 5 m/s.
a. How long will it take you to cross the river?
b. How far downstream will you be upon arriving at the opposite shore?
PS. This problem does NOT require the use of equations of motion -- only v = d/t.
3-4 are tricky ones and may require a symbolic solution.
3. The acceleration due to gravity on the Moon is 1/6 that of Earth. How does the time to fall (from a certain height) on the Moon compare to that the time to fall on the Earth from the same height?
4. If a ball falls from rest, and completes the second half of its path downward in 1 second, how high up was it when it was released. (You can also solve for the total time to fall, if that is helpful.)
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