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Power

A car maintains a maxiumum speed of 20 meters per second on an uphill road at an angle of 30 degrees. The weight of the car is 10,000 newtons. Determine
(a) Power needed to maintain the speed uphill in Kw.
(b) Minimum time it will take to accelerate from rest to 30 meters per second on a level road.
(c) Max speed it will be able to maintain if the angle is 20 degrees.

Solution Preview

(a) Component of weight along the hill is mg*cos60 = 0.5mg
but weight = mg = 10000 Newtons
--> Component of weight along the hill is = 5000 Newtons
Power = Force* velocity
Force needed = Component of weight along the hill = 5000 Newtons
--> Power = 5000*20 = 100000 Watts = 100 Kilowatts

(b) Force = 5000 = m(in kg)*a (acceleration)= 10000/9.81 * a
--> a = 4.905
v = v(0)+ at, v(0) = 0, v = 30 m/s
--> 30 = ...

Solution Summary

Calculates Power needed to maintain the speed uphill in Kw, minimum time it will take to accelerate from rest to 30 meters per second on a level road and maximum speed, the car will be able to maintain if the angle is 20 degrees.

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