Question

Calculate the change in momentum of a body weighing 5 kg when its velocity decreases from 20 m per second to 0.20 m per second

Answer 1

Change in momentum =Pf-Pi
=(m×v) - (m×v')
=(5×0.2) - (5×20)
=1 - 100
= -99

Answer 2

Explanation:

GIVEN :-

• Mass , m = 5 kg.

• Initial velocity , u = 20 m/s.

• Final velocity , v = 0.20 m/s.

TO FIND :-

• Change in momentum.

SOLUTION :-

$\\ : \implies \displaystyle \sf \: Change \: in \: momentum \ (\Delta p) = mv - mu$

$\\ : \implies \displaystyle \sf \: Change \: in \: momentum \ (\Delta p) = m(v - u) \ \: \: \: \: \: \: \: \: \: \: \: \bigg \lgroup common\bigg \rgroup$

$\\ : \implies \displaystyle \sf \: Change \: in \: momentum \ (\Delta p) = 5(0.20 - 20)$

$\\ : \implies \displaystyle \sf \: Change \: in \: momentum \ (\Delta p) = 1 - 100$

$\\ : \implies \underline{ \boxed{\displaystyle \sf \: Change \: in \: momentum \ (\Delta p) = - 99 \: kg \: ms^{ - 1} }}$

$\therefore \underline {\displaystyle \sf change \: in \: momentum \: of \: a \: body \: is \: -99 kg \: m/s.}$