Question

a force of 200N acts on a body of mass 25g and the body moves at a speed of 20m/s.Find the power developed by the force​

Answer 1

Answer:

0.125 W

Explanation:

Given that :

• Force = 200 N
• Mass of the body = 25g = 0.025 kg
• Velocity = 20 m/s

To find :

• Power developed by the force.

Solution :

We know that,

Momentum = Mass × Velocity

⇒ $\rho$ = 0.025 × 20

⇒ $\rho$ = 0.5 kg m/s.

Also,

Force = $\sf \dfrac{Momentum}{Time}$

⇒ 200 = $\sf \dfrac{0.5}{Time}$

⇒ Time = $\sf \dfrac{0.5}{200}$

⇒ Time = 0.025 seconds.

Now,

Power = Energy × Time

To find energy, we will use formula :

Energy = $\dfrac{1}{2}$ mv²

⇒ E = $\dfrac{1}{2}$ × 0.025 × 20²

⇒ E = 0.0125 × 20 × 20

⇒ E = 5 J

So, the energy is 5 J.

Now, find the power :

Power = Energy × Time

⇒ P = 5 × 0.025

⇒ P = 0.125 W

Hence, the required power is 0.125 W.