A boy of mass 50 kg runs up a staircase of 45 steps in 9 seconds. If the height of each step is 15 cm, find his power. Take g = 10 ms^-2.

Solution

Here we have,

Mass of the body, m = 50 kg

Total number of steps on the staircase = 45
Height of each step = 15 cm

So, height of the staircase, h = $45 \times \frac{15}{100} = 45 \times 0.15 = 6.75 m$

Time taken to climb each step = 9 sec

Now, weight of the boy, mg = 50 x 10 = 500 N

So, power of the boy, P = $\frac{Work done}{Total time taken}$

$= \frac{mgh}{t} = \frac{500 \times 6.75}{9} = 375 W$

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Matter In Our Surroundings

A boy of mass 50 kg runs up a staircase of 45 steps in 9 seconds. If the height of each step is 15 cm, find his power. Take g = 10 ms^-2.

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Mock Test Series

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Matter In Our Surroundings

A boy of mass 50 kg runs up a staircase of 45 steps in 9 seconds. If the height of each step is 15 cm, find his power. Take g = 10 ms-2.

Some More Questions From Matter In Our Surroundings Chapter

Convert the following temperature to Celsius scale.573 K

Convert the following temperatures to Kelvin scale25°C

What is the physical state of water at100 °C

For any substance, why does the temperature remain constant during the change of state ?

Suggest a method to liquify atmospheric gases.

Convert the following temperatures to Kelvin scale.35°C

Give reason for the following observations.Naphthalene balls disappear with time without leaving any solid.

Give reason for the following observations.We can get the smell of perfume sitting several metres away.

What is the physical state of water ata) 25°C b)00Cc)1000C

What is the physical state of water at0°C

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

A boy of mass 50 kg runs up a staircase of 45 steps in 9 seconds. If the height of each step is 15 cm, find his power. Take g = 10 ms^-2.

Convert the following temperature to Celsius scale.

573 K

Convert the following temperatures to Kelvin scale

25°C

What is the physical state of water at

100 °C

Convert the following temperatures to Kelvin scale.

35°C

Give reason for the following observations.

Naphthalene balls disappear with time without leaving any solid.

Give reason for the following observations.

We can get the smell of perfume sitting several metres away.

What is the physical state of water at

a) 25°C
b)0⁰C
c)100⁰C

What is the physical state of water at
0°C