Question

two racing cars acquire velocities 18 kmph and 36 kmph in 0.5s. If they are accelerated
uniformly from rest, find their accelerations.
1) 78m/s. 36m/s 2) 36m/s 72m/s 3) 10m/s. 20m/s? 4) 15m/s. 30m/s​

Answer 1

Answer:

3) 10 m/s^2, 20 m/s^2

$for \: first \: car \\ given \: \\ u = 0 \: \frac{m}{s} \\ v = 18 \: kmph = 18 \times \frac{5}{18} = 5 \: \frac{m}{s} \\ a = \frac{v - u}{t} \\ a = \frac{5 - 0}{0.5} \\ a = 10 \: \frac{m}{ {s}^{2} } \\ for \: second \: car \\ given \\ u = 0 \\ v = 36 \: kmph = 36 \times \frac{5}{18} = 10 \: \frac{m}{s} \\ a = \frac{v - u}{t} \\ a = \frac{10 - 0}{0.5} \\ a = 20 \: \frac{m}{ {s}^{2} }$