Question

(Numerical problems) A car is running with the velocity of 72km/h. What will be it's velocity after 5s if it's acceleration is -2m/s square​

Answer 1

The car's velocity after 5s : 10 m/s

Further explanation

Given

velocity=v=72 km/h=20 m/s

time=t = 5 s

acceleration=a = -2 m/s²

Required

velocity after 5s

Solution

Straight motion changes with constant acceleration

$\tt v_f=v_i+at$

vf=final velocity

vi = initial velocity

Input the value :

$\tt v_f=20+(-2).5\\\\v_f=20-10\\\\v_f=10~m/s$

The car is decelerating (acceleration is negative) so that its speed decreases