Question

A 81 kg man lying on a surface of negligible friction shoves a 79 g stone away from himself, giving it a speed of 4.5 m/s. What speed does the man acquire as a result?

Answer 1

Answer:

The speed of the man is 4.54 m/s.

Explanation:

Given that,

Mass of man=8100 g

Mass of stone = 79 g

Speed  = 4.5 m/s

We need to calculate the speed of the man

Using momentum of conservation

$(m_{1}+m_{2})V=m_{1}v_{1}+m_{2}v_{2}$

Where,

$m_{1}$=mass of man

$m_{2}$=mass of stone

$v_{1}$=velocity of man

$v_{2}$=velocity of stone

Put the value in the equation

As the stone is away from the man

So, the speed of stone is zero

$8179\times4.5=8100\times v+0$

$v=\dfrac{8179\times4.5}{8100}$

$v = 4.54\ m/s$

Hence, The speed of the man is 4.54 m/s.