Question

If a car at rest accelerates uniformly to a speed of 144 km/hour in 20 second it covers a distance of

• A. 400 m
• B. 1440 m
• C. 2880m
• D. 25m

Answer 1

Answer: (A)

400 m

Answer 2

u = 0, v = 144 km/hour $= 144 \times \frac{5}{18} m/ \sec$
$= 40 / m / \sec$
$v = u + at$
$\Rightarrow \, a = \frac{v - u}{t} = \frac{40 - 0 }{20} = 2 m / \sec^2$
$\therefore \, s = ut + \frac{1}{2} at^2$
$= \frac{1}{2} \times 2 \times (20)^2 = 400 m$