Question

a projectile is fired horizontally from a certain height calculate the time taken by it to reach the ground assuming the height to be 1960 m

Answer 1

Hope you understand....

Answer 2

We know that, for horizontal projectile motion, the vertical component of velocity is zero.

So, from second motion equation, H= 1/2 gt^2

hence t= √(2H/g)  -- (1)

here, we are given that,

H= 1960 m and assuming g= 10 m/s,

substituting the values in equation (1)

t= √2 x 1960/10 = 19.79 s

if g= 9.8 m/s

t = √ 2 x 1960/9.8 = 20 s