Question

A stone is dropped from a certain height which can reach the ground in 5sec.If the stone is stopped after 3seconds of its fall and then allowed to fall again,then the time taken by the stone to reach the ground for the remaining distance is...?
2sec
3sec
4sec
none of the above​

Answer 1

Answer:

Correct option is

C

4 s

Let h be the height, t=5 s

∴h=

2

1

gt

2

=

2

1

(9.8)(25)=122.5 m

Distance covered in 3 sec=

2

1

(9.8)(3)

2

=44.1 m

Remaining distance =122.5−44.1=78.4 m

If t s is the required time, then

78.4=0+

2

1

gt

2

⇒t

2

=

49

784

=16

⇒t=4s.

Answer 2

$\color{Red}{ANSWER:-}$

none of the above