Question

A ball is dropped from an upper floor, some unknown distance above your apartment. As you look out of your window, which is 1.50 m tall, you observe that it takes the ball 0.210 s to traverse the length of the window. 1)Determine how high above the top of your window the ball was dropped. Ignore the effects of air resistance. (Express your answer to three significant figures.)

Answer 1

Answer:1.902 m

Explanation:

Given

height of apartment=1.5 m

It takes 0.21 sec to reach the bottom from apartment

So

$s=u_1t+\frac{gt^2}{2}$

$1.5=u_1\times 0.21+\frac{9.81\times 0.21^2}{2}$

$u_1=6.11 m/s$

i.e. if ball is dropped from top its velocity at window is 6.11 m/s

So height of upper floor above window

$v^2-u^2=2as$

where s= height of upper floor above window

here u=0

$6.11^2=2\times 9.81\times s$

$s=\frac{6.11^2}{2\times 9.81}$

s=1.902 m