Question

A car traveling at 17.2 m/s skids to a stop in 188 m from the point where the brakes were applied.

In what distance would the car have stopped had it been going 58.5 m/s , if tires and road condition were unchanged (i.e. if the acceleration were the same)?

Answer 1

Initial speed of the car = V₁ = 17.2 m/s

Final speed of the car = V₂ = 0 m/s (Comes to a stop)

Distance the car travels before stopping = D₁ = 188 m

Acceleration of the car = a

V₂² = V₁² + 2aD₁

(0)² = (17.2)² + 2a(188)

a = -0.7868 m/s²

New initial speed of the car = V₃ = 58.5 m/s

New final speed of the car = V₄ = 0 m/s

New distance the car travels before stopping = D₂

All the conditions are same therefore the acceleration of the car is the same.

V₄² = V₃² + 2aD₂

(0)² = (58.5)² + 2(-0.7868)D₂

D₂ = 2175 m

Stopping distance of the car if it is going at a speed of 58.5 m/s = 2175 m/s