# Physics question help please!!!!!?

When a car with a mass of 10500 kg moves down the road its motion is resisted by surface friction and air resistance. For a certain car assume the combination of these resistive forces is F = 230 + 2.0v^2 such that when speed is in m/s, force is in Newtons. What the power developed by the car when it is accelerating at 0.25 m/s^2 with a speed of 12 m/s?

### 3 Answers

- oubaasLv 79 months agoFavourite answer
resistent force RF = 230+2*12^2 = 230+288 = 518 N

accelerating force AF = m*a = 10500/4 = 2625 N

power P = (RF+AF)*V/1000 = (2625+518)*12 /1000 = 37.72 kw

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- oldschoolLv 79 months ago
Power = F*v = Nm/s = J/s = Watts

The power required will be the mass times the acceleration*velocity + the loss power. [m*a + 230+2.0*v²]*v = [10,500*0.25 + 230+2.0*12²] *12 = 37,716 W

That is almost a 12 ton car which is not likely

Suppose that should be 1050kg

[1050*0.25 + 230+2.0*12²] *12 = 9,366 W

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- AshLv 79 months ago
F(net) = F(applied by the car) - F(friction)

ma = P/v - F(friction)

P/v = ma + F(friction)

P = v(ma + F(friction))

P = 12 (10500*0.25 + 230 + (2.0*12²))

P = 37716 W or 38 kW

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