Answer to Question #163908 in Physics for EUGINE HAWEZA

Question

Explain how you would measure the mass of an apple using a uniform meter rule, some string and a 100g mass.

Answer 1

If the mass of the meter stick is neglectable compared to the mass of apple and the 100g-weight, I would:

1. Hang the ruler at the middle so it is at the equilibrium

2. Attach the apple somewhere near the center of the ruler

3. Attach the weight to the other end of the ruler and slide it (or the weight and apple) till the ruler is at equilibrium again

4. Measure the distances from the center of the ruler to where the strings with apple (distance D) and weight (distance d) are attached

5. Use the following equation:

$$MD=md, \\\space\\ M=m\frac dD,$$

where m=100g.