Question

A boy mass 30Kg can go up 20 steps each of height 10cm in 20sec. Calculate the power of the boy. [g=9.8m/s²]​​

Answer 1

Question:-

• A boy mass 30Kg can go up 20 steps each of height 10cm in 20sec. Calculate the power of the boy. [g=9.8m/s²]

To Find:-

• Find the power of boy.

Solution:-

Given ,

• Mass of boy = 30 kg

• h is 20 × 10 = 200 cm = 2 m

• t = 20 sec

Formula to be Used:-

• Potential Energy = mgh

• $\sf \:Power \: of \: boy = \dfrac { Potential\: Energy } { Time }$

First ,

We have to find the Potential energy:-

$\sf\longrightarrow \: Potential \: Energy = mgh$

$\sf\longrightarrow \: Potential \: Energy = 30 \times 9.8 \times 2$

$\sf\longrightarrow \: Potential \: Energy = 588$

Now ,

We have to find the Power of boy:-

$\sf\longrightarrow \: Power = \dfrac { Potential \: Energy } { Time }$

$\sf\longrightarrow \: Power = \dfrac { 588 } { 20 }$

$\sf\longrightarrow \: Power = 29.4$

Hence ,

• Power of boy is 29.4W

Answer 2

Answer:

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• Mass of boy = 30 kg
• Height = 200 cm = 2m
• Time = 20 sec

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• Power of the boy

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First of all we will find the energy used:-

⇒ P.E = mgh

⇒ P.E = 30 × 9.8 × 2

⇒ P.E = 588

Now let's find the Power of the boy:-

⇒ Power = $\dfrac{P.E}{t}$

⇒ Power = $\dfrac{588}{20}$

⇒ Power = 29.4 Watt

Hence, the Power of the boy is 29.4W.

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