Question

A bus decreases from 80 km/h to 60 km/h in 5 seconds. Find the acceleration of the bus?

Answer 1

Dear Student,

$$\begin{gathered} \mathrm{u}=80\mathrm{km}/\mathrm{h}=80\times \frac{5}{18}\mathrm{m}/\mathrm{s} \\ \mathrm{u}=22.22\mathrm{m}/\mathrm{s} \\ \mathrm{v}=60\mathrm{km}/\mathrm{h}=60\times \frac{5}{18}\mathrm{m}/\mathrm{s}=16.67\mathrm{m}/\mathrm{s} \\ \mathrm{t}=5\mathrm{s} \\ \mathrm{a}=\frac{\mathrm{v}-\mathrm{u}}{\mathrm{t}} \\ \mathrm{a}=\frac{16.67-22.22}{5}=-1.11\mathrm{m}/{\mathrm{s}}^2 \\ \mathrm{Here}\mathrm{negative}\mathrm{sign}\mathrm{shows}\mathrm{the}\mathrm{retardation}\mathrm{of}\mathrm{the}\mathrm{bus}. \end{gathered}$$