Question

Does a car speedometer measure speed, velocity, or both? Explain.

Short answer

The speedometer measures only the speed of the car.

Step-by-step solution

Step 1. Definitions of speed and velocity

The rate at which an object is displaced from one location to another is known as the object’s velocity. It has both direction and magnitude.

The rate of change in the object’s distance is known as the object’s speed. It has magnitude but no direction.

Step 2. Application of speedometer

A speedometer is a device that helps to estimate and visualize a vehicle's instantaneous speed, that has only magnitude. The speedometer does not give the direction of the vehicle.

Thus, this device can measure only the speed of a vehicle, not its velocity.