Question

An observer standing in front of a 1.5 meter high window

he sees a stone thrown off the ground firstly go bottom to top and after a while top to bottom 

Stone sum Since the display time is 1 second

how high can this stone rise above the top of window

Answer 1

Given:

Time of flight = 1 s

According to Newton's Equation of Motion:

v = u + at

Where v = Final velocity

u = Initial velocity

a = Acceleration

t = Time taken

For stone at the top of its flight:

v = 0

⇒ 0 = u - gt    Where g = acceleration due to gravity

⇒ u = gt

Since time of flight is 1 second, time taken to reach the top point = 0.5 second

⇒ u = g/2 m/s

For hight reached:

v² - u² = 2as

0² - g²/4 = 2(-g)(s)

⇒ s = g/8 m

Taking g = 9.81 m/s²

s = 1.23 m

Therefore, the stone will reach a height of 1.23 m above the top of the window.