Question

A stone is projected at an angle of 45° with respect to the horizontal from the ground. The stone lands on the top edge of a building of height 5 m at a distance of 15 m from the point of projection. Then the initial speed of the stone is

(A) 15 ms−1 (B) 10 ms−1 (C) 20 ms−1 (D) 20 sqrt(2/3)

Answer 1

Answer:

Explanation

Time taken to reach the ground is given by

h=  

2

1

​  

gt  

2

--------(1)

Since horizontal displacement in time t is zero

∴t=  

f

2V

​  

-------(2)

h=  

f  

2

 

2gv  

2

 

​  

=20m

PLS MARK ME BRAINMEST