Chapter 4, Problem 46A

What is the acceleration of a car that moves at a steady velocity of 100 km/h due north for 100 seconds? Explain your answer and state why this question is an exercise in careful reading as well as physics.

To determine

The acceleration of a car that is moving with steady velocity.

To Explain: This is an exercise in careful reading as well as in physics.

Answer to Problem 46A

The acceleration of the car is zero.

Explanation of Solution

Introduction:

The change in displacement divided by time is called velocity. The change in velocity divided by time is called acceleration. Both velocity and acceleration are vector quantities.

Here in the question, it is given that the car is moving with constant velocity of 100 km/h for the given time interval, so one can understand that the car is in linear motion.

Since, the car is moving with constant velocity, the acceleration will be zero.

  $\text{Acceleration = }\frac{\text{Change in velocity}}{\text{Time taken}}$

Conclusion:

So, if change in velocity is zero, acceleration is zero.

This is an exercise question in careful reading as well as in physics because, the velocity will and time are provided and have different units. The key word in the question is ‘steady velocity’ due to which the acceleration is zero and no calculation is required.