Question

A ball is dropped from the edge of a roof. How long does it take to

fall 4.9m? (given acceleration =9.8m/s2)

Answer 1

using eqn:-

S=ut+$\frac{1}{2}$a*$t^{2}$

here,u=initial speed=0;
a=g=9.8 $\frac{m }{sec^{2}}$
S=4.9 m

i.e. 4.9 = 0.t +1/2*9.8*$t^{2}$

$\frac{4.9}{4.9}= t^{2}$[tex]

1=t^2

i.e t=1sec. 

Answer 2

Answer:

This is the correct answer

Hope it helps you