Question

A body of
mass 10 kg is moving with velocity
10 m/s. After applying external fonce,
its velocity becomes 20 m/s. calculate the
wonk
done on the
body.​

Answer 1

Given :

• Mass of body = 10kg
• Initial speed = v₁ = 10m/s
• Final speed = v₂ = 20m/s

To find :

Work done

Formula used :

• Kinetic energy = (1/2) × mass × (speed)²
• Work done = Change in kinetic energy

Solution :

The work done by force on body , increase its speed therefore the change in kinetic energy will equals to work done

W = KE₂ - KE₁

$\sf \implies \:W\:=\: \dfrac{1}{2} \times m \times (v_{2})^{2} \: - \: \dfrac{1}{2} \times m \times (v_{1})^{2}$

$\sf \implies \:W\:=\: \dfrac{1}{2} \times m \times \bigg( \: (v_{2})^{2} \: - (v_{1})^{2} \bigg)$

$\sf \implies \:W\:=\: \dfrac{1}{2} \times 10 \times \bigg( \: (20)^{2} \: - (10)^{2} \bigg)$

$\sf \implies \:W\:=\: \dfrac{1}{2} \times 10 \times \bigg( \: 400 \: - 100 \: \bigg)$

$\sf \implies \:W\:=\: 5 \times \bigg( \:300 \: \bigg)$

$\sf \implies \:W\:=\: 1500 \: J$

ANSWER :

Work done = 1500 J