# physics

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a car of mass 12,000 kjg is moving at 40m/s along a strong road. The driver brakes and the car goes 800 meters before stopping. What was the magnitude of the average force of friction (inN) between tires and road?

• physics -

Is the mass a typo?
12,000 kg is too big for a car

force * distance = change in kinetic energy

800 F = (1/2)(12,000 ?)(1600)

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