Chapter 32, Problem 45A

A pair of isolated protons will fly apart from each other. The same is true for a pair of isolated electrons. Your teacher asks which has the greater initial acceleration if the initial distance between the particles is the same. Sophia says the initial accelerations will be equal because the forces are equal. Sandra says no, that the electrons will accelerate more—but can’t explain why. Both look to you for your input. What is your thinking?

To determine

To identify: Whether the argument of person So or Sa is correct.

Answer to Problem 45A

Both are correct but not completely.

Explanation of Solution

Introduction:

When two like charges are placed together, then they repel each other as long as they experience their respective force.

When a pair of isolated protons or isolated electrons are distributed, then like charges oppose each other. Each pair of like charges will experience an equal force due to each other. But, their acceleration will not be equal. Thus, “So” is partially correct.

Since proton has a much greater mass compared to an electron. Thus, protons will experience lesser acceleration even for the same repelling force as compared to the electrons. Thus, “Sa” is correct too.

Conclusion:

As long as like charges experience their respective forces, it will keep moving apart. But, the acceleration of the protons will decrease for the same force. Thus, both are partially correct.