If the speed of a car is increased from 25 kmph to 40 kmph in 1 min, find the acceleration.

Concept:

Rate of change of velocity is known as acceleration. Its unit is m/s². It is a vector quantity.

a = change in velocity/time

Equations of motion:

• v = u + at
• v² – u² = 2as
• \(s = ut + \frac{1}{2}a{t^2}\)

Calculation:

\(u = 25\;kmph = 25 \times \frac{5}{{18}} = \frac{{125}}{{18}} = 6.94\;m/s\) 

\(v = 40\;kmph = 40 \times \frac{5}{{18}} = \frac{{200}}{{18}} = 11.11\;m/\;s\) 

t = 1 min = 60 s

\(a = \frac{{v - u}}{t} = \frac{{11.11 - 6.94}}{{60}} = 0.0695\;m/{s^2}\)