solve for the answer

Question

The diameter of wheels of a car is 63 cm. Find the number of rotations of the wheels when the car travels a distance of 1 km.

Answer 1

N=D/(πd), where D is the distance traveled and d is the diameter of the wheels.

Answer 2

Hi Dalia, 

 

To solve this problem you first need to find the circumference of the tire to know how much distance is covered by a single rotation of the tire.  The two numbers you are given have different units so it might be easiest to start off by converting both of these to a common unit of meters (m).

 

63cm=0.63m

1km=1,000m

 

Now lets find the circumference of the tire which is equal to the diameter multiplied by pi (C=d*π)

The circumference is (0.63m*3.14)=1.9782, I'm not sure how your teacher likes you to round numbers but that can be rounded to 1.98m.

 

This means that for each rotation of the tire the car travels 1.98m.

 

Now to travel 1,000m, how many times must you travel 1.98m?

 

This can be solved by dividing 1,000m by 1.98m (1000/1.98).  This gives 505.5, which is the number of rotations the tire must turn to travel a total of 1km.

 

Note: If you round 1.98m to 2m, the answer will come out to an even 500 rotations.  It depends how your teacher likes you to round.