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If a car generates 20 hp when traveling at a steady 70 km/h , what must be the average force exerted on the car due to friction and air resistance? Express your answer to two significant figures and include the appropriate units.

Respuesta :

Answer:

Force, [tex]F=7.6\times 10^2\ N[/tex]

Explanation:

Given that,

Power of the car, P = 20 hP

Since, 1 hP = 745.7 Watts

So, 20 hP = 14914 Watts

Speed of the car, v = 70 km/h = 19.45 m/s

The relation between the force, power and the speed is given by :

[tex]P=F\times v[/tex]

[tex]F=\dfrac{P}{v}[/tex]

[tex]F=\dfrac{14914\ W}{19.45\ m/s}[/tex]

F = 766.78 N

or

[tex]F=7.6\times 10^2\ N[/tex]

So, the force exerted on the car due to friction and air resistance is [tex]F=7.6\times 10^2\ N[/tex]. Hence, this is the required solution.

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