Question Details

A body released from a height h takes time t to reach earth’s surface. The time taken by the same body released from the same height to reach the moon’s surface is

Options

A

t

B

6t

C

√6 t

D

t/6

Correct Answer :

√6 t

Solution :

The correct option is √6 t.

To find the time taken by a body to reach the moon's surface when released from a height
h
, we can use the equations of motion under gravity.

For a body falling freely from rest (where initial velocity
u=0
) from a height
h
, the distance traveled
s=h
in time
t
is given by the second equation of motion:


s=ut+12gt2

Since the body is released from rest (
u=0
):


h=12gt2

Solving for time
t
, we get:


t=2hg

1. On Earth's Surface:
Let the acceleration due to gravity on Earth be
ge
and the time taken be
t
.
t=2hge

2. On the Moon's Surface:
Let the acceleration due to gravity on the Moon be
gm
and the time taken be
tm
. Since the body is released from the same height
h
:
tm=2hgm

We know that the acceleration due to gravity on the Moon is approximately one-sixth of that on Earth:
gm=ge6

Substituting this relationship into the expression for
tm
:


tm=2hge6

Simplifying the fraction:


tm=6×2hge


tm=6×2hge

Since the term under the second square root is the time taken on Earth (
t
), we can substitute it back:


tm=6t

Therefore, the time taken to reach the Moon's surface is √6 t.

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