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riadik2000 [5.3K]
3 years ago
11

A man has power of 90W and mass 60kg runs up a staircase in 40 second. If each step of staircase is 20m high calculate the numbe

r of steps
Physics
1 answer:
Zielflug [23.3K]3 years ago
5 0
Power is calculated by dividing the work done with the time interval of the motion. Work, on the other hand, is force times the distance traveled. Therefore, we can calculate as follows:<span>

Power=W/t = mgd/t
90 = 60(9.81)d / 40
d = 6.12 m

Number of steps = 20/6.12 = 3.27 or 3 steps</span>
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s = ut + (\frac{1}{2}) at^{2}

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(B) If the pelican was traveling at the same speed but was only 1.5 m above the water, how far would the fish travel horizontally before hitting the water below?

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pelican's speed = 9.5 m/s

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s = ut + (\frac{1}{2}) at^{2}

since u = 0

s =  (\frac{1}{2}) at^{2}

t = \sqrt{\frac{2s}{a} }

where a = acceleration due to gravity and s = vertical height

t = \sqrt{\frac{2 x 1.5 }{9.8} } = 0.55 s

 

distance traveled by the fish = speed x time = 9.5 x 0.55 = 5.225 m

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