Question

A truck travelling at 45 km/hr is slow down to 30 km/hr in 10 sec. Find the acceleration( or retardation).

Answer 1

Given,

Initial velocity,u=45km/h

= 45000/3600 =12.5 m/s

Final velocity,v= 30km/h

= 30000/3600 =25/3 m/s

t=10s

Acceleration= change in velocity/ time

a=v- u/t

a = 25/2- 25/3

=75- 50/6

=25/6 m/s^2

= 4.16 m/s^2.

Answer 2

45km/hr=12.5m/s

30km/hr=8.34m/s

a=v-u/t

= 4.2/10=0.42m/ssquare