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A 1200-kg car comes to rest from a speed of 25 m/s in a distance of 75 m. If the brakes are the only thing making the car come to a stop, ca
Question
A 1200-kg car comes to rest from a speed of 25 m/s in a distance of 75 m. If the brakes are the only thing making the car come to a stop, calculate the magnitude of the force that the brakes apply on the car.
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Physics
3 years
2021-08-19T09:11:17+00:00
2021-08-19T09:11:17+00:00 1 Answers
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Answers ( )
Answer:
5000 N
Explanation:
First we need to calculate the acceleration the car had.
We can do that using Torricelli formula:
V^2 = Vo^2 + 2aDS,
where V = 0, Vo = 25, DS = 75
0 = 25^2 + 2*a*75
150a = -625
a = -4.1667 m/s^2
The force is calculated multiplying the mass and the acceleration, so:
F = m*a = 1200 * (-4.1667) = -5000 N
The magnitude of the break force is 5000 N (the sign only indicates the direction, the magnitude is only the value without sign)