Question

1. A stone dropped from a height of 90 cm
above the top of a window of 160 cm high.
The time taken by the stone to cross the
indow is​

Answer 1

Answer:

time taken =approx 7 sec

Explanation:

s=90+160=250m

s=ut+1/2gt^2

u=0

Answer 2

Answer:

The time taken by the stone to cross the  window is​ 7.1 sec.

Explanation:

Given that,

Height of window = 160 cm

Height =90 cm

We need to calculate the time

Using equation of motion

$s=ut+\dfrac{1}{2}gt^2$

Where, s = total height

g = acceleration due to gravity

u = initial velocity

Put the value into the formula

$250=0+\dfrac{1}{2}\times9.8\times t^2$

$t^2=\dfrac{2\times250}{9.8}$

$t=\sqrt{51.0}$

$t=7.1\ sec$

Hence, The time taken by the stone to cross the  window is​ 7.1 sec.