Question

4. A boy of mass 50 kg runs up to a staircase of 45 steps in 5 s. If the height of a step is 15 cm find the power. g=10
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Answer 1

Solution:

Given:

Mass of body (m) = 50 kg

Total no. of steps on the staircase = 45

And:

Height of each step = 15 cm

Time taken to climb each step (t) = 9 sec

Now:

Height of the staircase (h):

$\implies$ 45 × 15

$\implies$ 6.75 m

We know that:

Weight of the boy (mg) = 50 × 10 = 500 N

Using this formula:

$\boxed{\sf{P= \frac{Work \: done }{Total \: time \: taken}}}$

We get:

$\sf{P = \frac{mgh}{t}}$

$\sf{P = \frac{500 \times 6.75}{9}}$

$\sf{P = 375 \: W}$

Therefore:

Power is: 375 W

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Answered by: Niki Swar, Goa❤️