Question

If a car at rest accelerates uniformly to a speed of 144 km/h in 20 s. Then it covers a distance of

• A. 20 m
• B. 400 m
• C. 1440 m
• D. 2880 m

Answer 1

Answer: (B)

400 m

Answer 2

Here$v = 144\mspace{6mu} km/h = 40m/s$

$v = u + at$ ⇒ $40 = 0 + 20 \times a \Rightarrow a = 2\mspace{6mu} m/s^{2}$

$\therefore$ $s = \frac{1}{2}at^{2} = \frac{1}{2} \times 2 \times (20)^{2} = 400\mspace{6mu} m$