Question

A scooterist covers a distance of 3 kilometres in 5 minutes. Calculate his speed in:
(a) centimetres per second (cm/s)
(b) metres per second (m/s)
​(c) kilometres per hour (km/h)

Answer 1

(a) Distance covered by the scooterist = 3 km = 3$\times$10⁵ cm

Time taken = 5 minutes = 300 seconds

Speed = $\frac{\mathrm{Distance}}{\mathrm{Time}}=\frac{3\times {10}^5\mathrm{cm}}{300\mathrm{s}}=1000\mathrm{cm}/\mathrm{s}$

(b) Distance covered by the scooterist = 3 km = 3$\times$10³ m

Time taken = 5 minutes = 300 seconds

Speed = $\frac{\mathrm{Distance}}{\mathrm{Time}}=\frac{3\times {10}^3\mathrm{cm}}{300\mathrm{s}}=10\mathrm{m}/\mathrm{s}$

(c) Distance covered by the scooterist = 3 km

Time taken = 5 minutes = $\frac{5}{60}\mathrm{hours}$

Speed = $\frac{\mathrm{Distance}}{\mathrm{Time}}=\frac{3\mathrm{km}}{{\displaystyle \frac{5}{60}}\mathrm{h}}=36\mathrm{km}/\mathrm{h}$