The braking distance of a car moving at a certain speed is 20 meters.
| June 10, 2021 | education
The braking distance of a car moving at a certain speed is 20 meters. What will be the braking distance if the speed at the beginning of braking increases by 2 times?
To find the braking distance after an increase in the initial speed, we use the ratio (the acceleration of the car remains unchanged, since the acting friction force is constant): S2 / S1 = (Vn2 ^ 2 / 2a) / (Vn1 ^ 2 / 2a) = Vn2 ^ 2 / Vn1 ^ 2, whence we express: S2 = Vн2 ^ 2 * S1 / Vн1 ^ 2.
Variable values: Vn ^ 2 (second initial speed) = 2Vn1 (first initial speed); S1 (first braking distance) = 20 m.
Calculation: S2 = Vn2 ^ 2 * S1 / Vn1 ^ 2 = (2Vn1) ^ 2 * 20 / Vn1 ^ 2 = 4 * 20 = 80 m.
Answer: The braking distance will be 80 m.
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