A girl of mass 40 kg runs up a staircase of 30 steps in 10 s. If the height of each step is 0.1 m, find the power developed by her. Take g = 10 \small ms^{-2}
112 W
1200 W
120 W
133 W
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Explanation:
Explanation:A girl of mass 40 kg runs up a flight of 15 steps each 15 cm high in 10 s. Find: (i) the work done and (ii) the power developed by him Take g = 10 N kg-1
Explanation:A girl of mass 40 kg runs up a flight of 15 steps each 15 cm high in 10 s. Find: (i) the work done and (ii) the power developed by him Take g = 10 N kg-1Force of gravity on boy F= mg = 40 × 10 = 400N Total distance covered in 15 steps , S = 15 × 15cm = 225cm = 2.25m Work done by the boy in climbing = Force x distance moved in direction of force Work, W = F × S = 400 × 2.25 = 900J Power developed = work done/time takrn = 900J/10s = 90W
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Given:
A girl of mass 40 kg runs up a staircase of 30 steps in 10 s
To find:
the power developed by the girl
Solution:
It is given that the girl is climbing the stairs so the work done by the girl will be given by:
Work = mgh
where
m = 40 kg
g = 10 m/sec²
h = 0.1 × 30 = 3 m
Work = 40×10×3
Work = 1200 joules
and the power developed by the girl is given by:
Power = work/time
Work = 1200 J
Time = 10 sec
Power = 1200/10
Power = 120 Watt
Hence, the power developed by the girl 120 W
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