A ball is projected vertically upwards from the ground at a speed of 9ms^-1. Assume that air resistance is negligible. Take the upward direction to be positive.
Find the distance travelled by the ball before it returns to the ground.
f.4 phys,,,
2008-10-18 7:18 pm
回答 (1)
2008-10-18 8:40 pm
✔ 最佳答案
Use equation of motion to find the maximum height h reached by the ball.u = 9 m/s, a = -g(=-10 m/s2), v = 0 m/s, s = h
use v^2 = u^2 + 2.a.s
0 = 9^2 + 2x(-10).h
i.e. h = 4.05 m
Since the max height reached by the ball is 4.05m, when it falls down to the ground, the ball will travel the same distance of 4.05 m.
Hence, total distance travelled by the ball = 2x4.05 m = 8.1 m
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