Question

Which device is used to measure the distance covered by the vehicle?

Answer 1

To measure the distance travelled by the car is measured by the device called odometer

Answer 2

Odometer is the device which is used to measure the distance covered by a vehicle.

Working:

An odometer basically counts the number of rotations made by the wheels of vehicle.

The radius of wheels is known.
So, the distance travelled by the vehicle is equal to the number is rotations multiplied by the circumference of the wheel.

That is,
Distance = n×2×π×r

where n = no. of rotations
And r = radius of the wheel


If the tyres are flattened out due to lack of pressure of air, then radius changes. In that case, there will be some error in the reading of odometer.