Question

A body of mass 500 g collides against a wall with a velocity of 10 ms
-1
and rebounds with the same speed. Its cha
(A)
10 kg ms-1
(B)
100 kg ms -1
(C) 0.5 kg ms
--1
(D)
1000 kg ms
-1
R​

Answer 1

Explanation:

p=mv

p=500×10

p=1000kg ms-1

Answer 2

Given,

A body of mass 500 g collides against a wall with a velocity of 10 ms.

To Find,

Its change in momentum =?

Solution,

We can find the change in its momentum as follows:

It is given that a body of mass 500 g collides against a wall with a velocity of 10 m/s.

We know that the change in momentum is equal to the mass of the body into the change in its velocity.

Δ$p = m*$Δ$v$

Where, Δ$p =$ Change in momentum

              $m =$ Mass of the body

             Δ$v =$ Change in velocity

Now,

The change in velocity is equal to the difference between the initial velocity and the rebound velocity.

Δ$v =$ $initial - rebound$

    $= 10 - (-10)$       (The velocity is negative as the body travels in the    

       $= 20 m/s$             opposite direction)

Now,

$m = 500 g$

Let us convert it to kilograms.

$1 g = 0.001 kg$

$500 g = 500*0.001 kg = 0.5 kg$

Now,

The change in momentum = mass x change in velocity

                                            $= 0.5*20$

                                             $= 10$ $kg ms^{-1}$

hence, the change in momentum is equal to (A) 10 kg ms-1.