Bill and Ben are standing on a cliff. Bill throws a ball exactly horizontally over the edge of the cliff at 20 ms−1. Ben has an identical ball which he drops straight down. Assume that air resistance is negligible.
(a) Which ball will hit the ground first, explaining why?
(b) If Ben’s ball had weighed twice as much, which ball would hit the ground first? Explain your answer.
(c) If the cliff is 45 m high how long does it take for Ben’s ball to hit the ground?
Note: by answering, you are not doing my homework. I am studying for exams and this was a past exam question, thanks!
(a) Which ball will hit the ground first, explaining why?
(b) If Ben’s ball had weighed twice as much, which ball would hit the ground first? Explain your answer.
(c) If the cliff is 45 m high how long does it take for Ben’s ball to hit the ground?
Note: by answering, you are not doing my homework. I am studying for exams and this was a past exam question, thanks!
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(a) Both hit the ground at the same time.
The vertical component of their motion is determined by gravity only.
(b) Both hit the ground at the same time.
mg (the weight) = ma, so a=g regardless of m.
(c) 45 m = (1/2) g t^2
t = sqrt (90 m/ 9.8 m/s^2) = 3.03 seconds.
The vertical component of their motion is determined by gravity only.
(b) Both hit the ground at the same time.
mg (the weight) = ma, so a=g regardless of m.
(c) 45 m = (1/2) g t^2
t = sqrt (90 m/ 9.8 m/s^2) = 3.03 seconds.