Question

A car travelling at 20km/h, it speeds up to 60km/h in 6 seconds. What is its acceleration?

Answer 1

A = (v - u) / t
v = 60*5/18 = 16.66
u = 20*5/18 = 5.55
t = 6s
= 16.66 - 5.55 / 6
= 11.11 / 6
= 1.85 m/s sq.

Answer 2

Acceleration is rate of change of speed.
Final speed, v = 60 km/h =60×(5/18) =50/3 m/s
initial speed,u = 20 km/h =20×(5/18)= 50/9 m/s
acceleration= (v-u)/t = [(50/3)-(50/9)]/6 = [50×(2/9)]/6 = 100/54 = 50/27 m/s²
                   = 1.85 m/s²