Question

Express the following speeds in km/h.
(a) 65km/h
(b) 40km/h
(c) 100m/s
(d) 10 m/s

Answer 1

We know:

1000 m = 1 km
1 m = (1/1000) km

Also,

(60 $\times$ 60) s or 3600 s = 1 h
1 s = (1/3600) h

(a) 65 m/s $=\frac{(65/1000)}{(1/3600)}$
$=234\mathrm{km}/\mathrm{h}$

(b) 40 m/s $=\frac{(40/1000)}{(1/3600)}$
$=144\mathrm{km}/\mathrm{h}$

(c) 100 m/s $=\frac{(100/1000)}{(1/3600)}$
$=360\mathrm{km}/\mathrm{h}$

(d) 10 m /s $=\frac{(10/1000)}{(1/3600)}$
$=36\mathrm{km}/\mathrm{h}$