Chapter 19, Problem 26A

Stand on a bathroom scale and read your weight. When you lift one foot up so you're standing on the other foot, does the reading change? Does a scale read force or pressure?

To determine

Whether the reading of bathroom scale differs while standing on one foot as compared to while standing on two feet.

Whether the scale measures force or pressure.

Explanation of Solution

The reading will be same for both of the cases, because here the bathroom scale measures force, not the pressure on it.

Here, force is the weight of the person and pressure is the force divided by the area of feet of the person. When one foot is lift up, area decreases and pressure increases but the weight of the person remains the same. So, the reading of the scale also remains the same.

Conclusion:

The reading will be the same for two cases.