Question

a bicycle wheel diameter 56cm is making 45 revolution in every 10 seconds . at what speed in km/hr is the bicycle traveling

Answer 1

Diameter of bicycle wheel, d = 56 cm

We know that circumference of circle is equal to the product of pi ( π ) and diameter so,

Circumference of the wheel = π * d
C = 22/7 * 56
C = 22 * 8
C = 176 cm
=> Circumference of the wheel = 176 cm

We know that circumference of the wheel is the distance travelled by the wheel in one revolution so,

Circumference of wheel = Distance travelled by wheel in 1 revolution

Distance travelled by wheel in 1 revolution = 176 cm

By simple unitary method we can find the distance travelled by the wheel in 45 revolutions,
Distance traveller by wheel in 45 revolutions, S = 45 * 176
S = 7920 cm

Now we have got the information that the wheel covers 7920 cm in 10 seconds therefore,

Speed of the wheel = S / t
Speed = 7920 / 10 = 792 cm/s
Speed = ( 792 / 100 ) m/s
Speed = 7.92 m / s
Speed = { ( 7.92 * 3600 ) / ( 1000 ) } km / hr
Speed = ( 0.792 * 36 ) km / hr
Speed of the wheel = 28.512 km / hr

Speed of the wheel = Speed of the bicycle
Speed of bicycle = 28.512 km / hr