Question

a body of mass 250 kg is changing it's speed from 54 km/h to 162 km/h after covering the distance of 80m. calculate the force and acceleration.

Answer 1

$here$
$m = 250kg \\ u = 54km {hr}^{ - 1} = 54 \times \frac{5}{18} \\ = 15m {sec}^{ - 1}$
$v = 162km {sec}^{ - 1} = 162 \times \frac{5}{18} \\ = 45m {sec}^{ - 1}$
${v}^{2} = {u}^{2} + 2as$
${45}^{2} = {15}^{2} + 2 \times a \times 80$
$160a = 1800$
$a = \frac{1800}{160}$
$a = 11.25m {s}^{ - 2}$
$acceleration = 11.25m {s}^{ - 2}$
$force = mass \times acc.$
$\: \: \: \: \: \: \: \: \: \: \: \: \: = 250 \times 11.25$
$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 2812.5$