Question

A wheel of diameter 42cm, makes 240 revolutions per minute. Find. (i) the total distance covered by wheel in one minute (ii) the speed of the wheel in km /h

Answer 1

diameter of the wheel=42cm
radius=42÷2=21
circumference of a circle =2πr
=2×22/7×21
=132cm
revolution in one minute=240
total distance=240×132=31680cm=0.31km
speed=0.3168÷60
=.000528km/hr

Answer 2

Answer:

The total distance covered by wheel in one minute is 0.3168 km and  the speed of the wheel in 19.008 km/hr

Step-by-step explanation:

Diameter of wheel = 42 cm

Radius of wheel = $\frac{42}{2}=21 cm$

Circumference of wheel = $2 \pi r$

                                        = $2 \times \frac{22}{7} \times 21$

                                        = $132 cm$

Distance traveled in 1 revolution = 132 cm

Distance traveled in 240 revolutions = $132 \times 240$

                                                              = $31680 cm$

Distance traveled in 1 minute = 31680 cm =0.3168 km

60 minute = 1 hour

1 minute = $\frac{1}{60} hr$

The speed of the wheel = $\frac{0.3168}{\frac{1}{60}}$

                                        = $19.008km/hr$

The total distance covered by wheel in one minute is 0.3168 km and  the speed of the wheel in 19.008 km/hr