Question

A meter stick of uniform density is pivoted at the 75 cm mark and a 250 g mass is placed at the 90.0 cm mark. If it balances the meter stick, what is the mass of the meter stick

Answer 1

The mass of the meter stick is 50 g.

Step-by-step explanation:

make a sketch of the problem statement;

0-------------------------------------------------75cm------90cm-----100cm

↓ Δ ↓

W 250 g

where;

W is the mass of the meter stick

Apply the principle of moment; take moment about the pivot.

sum of the anticlockwise moment = sum of the clockwise moment

W(75 - 0) = 250(90 - 75)

W(75) = 250(15)

W(75) = 3750

W = 3750 / 75

W = 50 g

Therefore, the mass of the meter rule is 50 g.