Question

1. A stone is dropped from the tip of a tower with zero initial velocity. It reaches the ground in 4 second. Then the height of the
tower is (g = 9.8 ms^-2)​

Answer 1

Answer:

use the Newton's equation

s=ut+1/2at^2

u=0

t=4

Answer 2

Answer: u = 0 ( because it is dropped not thrown )

a = 9.8m/s^(2)

t = 4 s

now , s = ut + {( at^2)/2}

=> s = 0 + {(9.8 × 16)÷2 } [bcoz u is 0, & t^2 is 16 ]

=> s= 78.4m

Here, downward direction is positive so value of g is simply taken as 9.8 instead of -9.8 and this is the reason displacement comes positive too.