Chapter 2, Problem 7RQ

How can you both at rest and also moving at $100,000\text{km/h}$ at same time?

To determine

To-determine: The reason that a person can be both at rest and also moving at $100,000\text{km/h}$ at the same time.

Answer to Problem 7RQ

The reason that a person can be both at rest and also moving at $100,000\text{km/h}$ at the same time because a person can be at rest with respect to Earth is moving at same velocity.

Explanation of Solution

Relative speed is defined as the speed of an object concerning the other moving or fixed object. If two objects were moving in the same direction and with the same velocity, then its relative speed is zero. Similarly, if two objects move with the same magnitude of velocity but have opposite directions, then the relative velocity of both objects, respect to each other is equal to double of the actual speed.

If a person is not moving or is at rest on the Earth which is revolving with speed of $100,000\text{km/h}$. Then the relative speed of the person and Earth concerning each other is equal to zero in magnitude. But the speed with respect to outer space is the Earth's revolving speed. Thus, in this way a person can be both at rest and also moving at $100,000\text{km/h}$ at the same time.

Conclusion:

Therefore, the reason that a person can be both at rest and also moving at $100,000\text{km/h}$ at the same time because a person can be at rest with respect to Earth is moving at same velocity.