Question

A car of mass 1000 kg starts moving with initial velocity 30 m/s with constant acceleration 5 m/s2. The distance travelled by the car when its velocity changes to 50 m/s is

Answer 1

using 3rd equation of motion
2aS=
${ v }^{2} - {u}^{2}$
2×5×S=
${50}^{2} - {30}^{2}$
=10S=2500-900
=10S=1600
S=1600/10=160m

Answer 2

Using third kinematical equation v^2 = u^2 + 2as
You can get the distance travelled by the car.. it's irrespective of the mass of the car
Thus
50*50 = 30*30+ 2*5*s
2500-900/10 = s
160 m = s
Thus 160 m is the distance travelled by the car