Question

A body of mass 20 gram changes its linear momentum from 8 kilogram metre per second to 4 kilogram metre per second , calculate its work done

Answer 1

$\rm\small\green{Given:-}$

• Mass = 20 gram.

• Momentum = 8 kilogram per second.

• Second = 4 kilogram per second.

$\rm\small\green{Find:-}$

• Calculate its work done.

$\rm\small\green{Solution:-}$

$\rm\rightarrow K . E = \frac{1}{2} m( {v}^{2} - {u}^{2} )$

$\rm\rightarrow K.E = \frac{1}{2} {mv}^{2} = \frac{ {m}^{2} {v}^{2} }{2m} = \frac{ {b}^{2} }{2m}$

$\rm\rightarrow W = \frac{( p_{(1)} - p_{(2)} ) }{2 \times 2m} = \frac{(4 - 8) ^{2} }{2 \times 20 \times {10}^{ - 3} }$

$\rm\rightarrow W = \frac{(4 - 8) ^{2} }{4 \times {10}^{ - 3} } = \frac{( - 4) ^{2} }{4 \times {10}^{ - 3} } = \frac{16}{40 \times {13}^{ - 3} }$

$\rm\rightarrow W = \frac{ \cancel{16000}}{ \cancel{40}}$

$\rm\rightarrow \fbox \green{ W = 400 \: j}$

$\rule{39mm}{1mm}$