Question

The diameter of a wheel is 14 m. The number of revolutions it will make to travel a 11 km will be (a) 300 (c) 250 (d) 350 (b) 200​

Answer 1

Answer:

Correct option is

A

250

Speed of the bus = 66 km/hr

Distance covered by the wheel in one minute =

60

66×1000×100

=110000 cm

Circumference of the wheel = 2×

7

22

×70=440 cm

Therefore, distance covered by the wheel in one revolution = 440 cm

Hence, number of revolutions in one minute =

440

110000

=250

Answer 2

Given,

Diameter of the wheel = 14 metres

To find,

Number of revolutions needed by the wheel to cover a distance of 11 kilometres.

Solution,

We can simply solve this mathematical problem by using the following mathematical process.

The radius of the wheel = Diameter ÷ 2 = 14÷2 = 7 metres

Circumference of the wheel = 2 × π × radius = 2 × (22/7) × 7 = 44 metres

Now,

Distance travelled in one revolution = Circumference of the wheel = 44 metres

Total distance to travel = 11 km = 11000 metres (As, 1 km = 1000 m)

So,

44 metres can be travelled in = 1 revolution

1 metre can be travelled in = (1/44) revolution

11000 metres can be travelled in = (1×11000)/44 = 250 revolutions

(This can be considered as the final result.)

Hence, the wheel will make 250 revolutions to travel 11 kilometres.