Question

The wheel of a bicycle has a diameter of 70cm and makes 2revolutions per second.calculate to one decimal place the speed of the bicycle in km/h

Answer 1

Explanation:

Number of reveloutions made in 1 second = 2

Number of revolutions made in 60 seconds ( 1 minute) = 2*60 = 120

Number of revolutions made in (60 minutes) 1 hour = 120 *60 = 7200

Circumference of circle = πd

`= (22)/(7)*70\\\\\\= 22*10\\\\= 220 cm`

The distance traveled in 1 revoultion = the circumference of the cirlcle

= 220 cm

The distance travelled in 7200 revoultion = 7200 * 220

=1584000 cm

= 1584000 ÷ 100000

= 15.84 km

= 15.8 km

Speed = 15.8 km/h