Question

a stone is thrown vertically upward with a speed of 20 m/s from a tower of height 100 m. find how much it will take to hit the ground​

Answer 1

Answer:

5seconds

Explanation:

time=distance/Speed

Answer 2

Answer:

given : initial velocity(u) = 20m/s

displacement (s)= 100 m

acceleration (a)= 10 m/s^2

now since the acceleration is constant throughout, we can apply equation of motion

s= ut+1/2at^2

now taking downward direction as positive and upward direction as negative

100 = (-20)t +1/2(10t^2)

5t^2-20t-100=0

on solving , we get

t= 2+√24 secs

t = 6.89 seconds