Chapter 2, Problem 3TE

If the speedometer of a car reads a constant speed of $50\text{km/h}$ , can you say that the car has a constant velocity? Why or why not?

To determine

To-determine: Whether the car has a constant velocity or not, when the speedometer of a car reads a constant speed of $50\text{km/h}$.

Answer to Problem 3TE

When the speedometer of a car reads a constant speed of $50\text{km/h}$ , it doesn’t mean that the velocity of car is constant because the direction of car can vary.

Explanation of Solution

The velocity is a quantity that provides magnitude as well as direction, whereas the quantity speed only gives magnitude. When the speedometer of the car reads a constant speed, it doesn’t mean that the car has constant velocity. It is because the direction of the car can vary while the magnitude is consistent. The speed as well as the direction, both should be constant to gain a constant velocity. So, even a car has a constant speed, and the direction can change, which will result in a change in velocity.

Conclusion:

Therefore, when the speedometer of a car reads a constant speed of $50\text{km/h}$ , it doesn’t means that the velocity of car is constant because the direction of car can vary.