Question

.certain force acting on a 20 kg mass changes its velocity from 5 metre per second to 20 metre per second calculate the work done by the force​

Answer 1

Hey Pretty Stranger!

The work done by the force will be equal to the change in kinetic energy when the velocity changes from 5m/s to 2m/s

i) In the first case :

• Mass,m = 200 g

• Velocity, v = 5m/s

★ K.E. = ½ mv²

→ K.E. = ½ × 20 × (5)²

→ K.E. = ½ × 20 × 25

→ K.E. = 250 J

i) In the second case :

• Mass,m = 20 kg

• Velocity,v = 2m/s

★ K.E. = ½ mv²

→ K.E. = ½ × 20 × (2)²

→ K.E. = ½ × 20 × 4

→ K.E. = 40 J

★ Work done by force = Change in kinetic energy

→ 250 - 40 J

→ 210 J

$\therefore$ Work done by the force is 210 J.