Question

A stone is thrown vertically upwards with a initial speed of 10 m/s from the edge of the roof of the house of Height H=20 m

a) how long does it takes for the stone to hit the ground
b) At what velocity it will hit the ground​

Answer 1

Answer: here is your answer please mark me as brainlest

Explanation: Answer

Correct option is

D

10 m

Let u be the initial velocity and h be the maximum height attained by the stone.

v  

1

2

​

=u  

2

−2gh,

(10)  

2

=u  

2

−2×10×  

2

h

​

 

100=u  

2

−10h ....(i)

Again at height h,

v  

2

2

​

=u  

2

−2gh

(0)  

2

=u  

2

−2×10×h

u  

2

=20h  ... (ii)

So, from Eqs. (i) and (ii) we have

100=10h

h=10m