Question

Question 4

Answer 1

The car requires 192 ft to stop from a speed of 48 mph

Explanation:

Given:

Speed, u = 30 mph

Stopping distance, d = 75 feet

The stopping distance d of a car after the brakes are applied varies directly as the square of the speed, u

So,

d = k (u)²

On substituting the value:

75 = k (30)²

k = $\frac{75}{900} \frac{ft hr^2}{miles^2}$

Speed, u₂ = 48 mph

d₂ = ?

d₂ = k (u₂)²

On substituting the values we get:

d₂ = $\frac{75}{900} X (48)^2$

d₂ = 192 ft