Question

two cars travelling towards each other on a straight road at velocity 10 m/s and 12 m/s respectively.when they are 150 m apart,drivers apply their brakes and each can decelerate at 2 m/s until it stops.how far apart will they be when they have both come to stop?

Answer 1

Question#19300

two cars travelling towards each other on a straight road at velocity 10 m/s and 12 m/s respectively. when they are 150 m apart, drivers apply their brakes and each can decelerate at 2 m/s until it stops. how far apart will they be when they have both come to stop?

Solution:

Let:

V₁ = 10 m/s

V₂ = 12 m/s

S₀ = 150 m

a = 2 m/s²

S - ?

S = S₀ + S₁ + S₂, were S₁, S₂ brake distance of the cars.

S₁ = 1/2at², were t - time of brakes

Such V₁ = at, t = V₁/a;

S₁ = V₁² / 2a;

S₂ = V₂² / 2a;

S = S₀ + (V₁² + V₂²) / 2a

S = 150 + (10² + 12²) / 2 * 2 = 211 m

Answer: 211 m.