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41 votes
41 votes
A dog  races up the stairs in a time of 1.80 seconds.  If the stairs are 12 feet high, how much power in hp is the dog putting out?  The weight of the dog is 48 lbs

User NidhinSPradeep
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2.6k points

1 Answer

10 votes
10 votes

The time taken by the dog to climb the stairs, t=1.80 s

The height of the stairs, h= 12 feet=3.66 m

The weight of the dog, m=48 lbs=21.77 kg

The work done by the dog in climbing up the stairs is,


W=\text{mgh}

Where g is the acceleration due to gravity.

On substituting the known values,


W=21.77*9.8*3.66=780.85\text{ J}

The power is given by,


P=(W)/(t)

On substituting the known values,


P=(780.85)/(1.80)=433.80\text{ J/s}

1 J/s = 1.34×10³ hp

Therefore,


433.80\text{ J/s=433.80}*1.34*10^3\text{ hp=581.3}*10^3\text{ hp}

Therefore the power put out by the dog is 581.3×10³ hp

User Hetptis
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