Question

A boy of 450N weight climbs a wood steps with a length of 3m.The boy takes 6 seconds to get the end of the steps. what is the power by the boy in this activity? Pls reply pls.......

Answer 1

power = work / time

and work = Force * distance

so, P =( 450 * 3 )/6 = 225 watt

hope it helps :)

Answer 2

Given:

A boy climbs 3m in 6s. The weight of the boy given is 450N.

To FInd:

The power utilized by the boy, $P=?$

Solution:

We know that Power is the rate at which work is done or energy is used

   $P=\frac{dW}{dt}$

Now, $W=Fx$, where $F$ is the force applied to a body, and $x$ is the distance traversed by the body in the same direction as the force.

∴ $P=\frac{d}{dt}(Fx)$

If a constant force is applied to the body,

   $P=F\frac{dx}{dt}$

⇒$P=Fv$, where $v$ is the speed of the body.

In this case, the force applied by the boy against the gravity, $F=450N$

The average speed of the boy,$v=\frac{Distance}{Time}=\frac{3m}{6s} =0.5m/s$

Power delivered by the boy, $P=Fv=450N*0.5m/s=225W$

Hence, the power delivered by the boy is 225 Watts