Question

A car is moving along a straight horizontal road with a velocity of 72 km h^–1. If m_s = 0.5, then the shortest distance in which the car can be stopped is [Take g = 10 ms^–2].

• A. 40 m
• B. 80 m
• C. 100 m
• D. 120 m

Answer 1

Answer: (A)

40 m

Answer 2

v² = u² + 2as Ž 0 = u² + 2(– mg)s

s = $\frac{u^{2}}{2\mu g} = \frac{(20)^{2}}{2 \times 0.5 \times 10}$