A meter stick has a mass of 0.21 kg and balances at its center. When a small chain is suspended from one end, the balance point moves 14.0 cm toward the end with the chain. Determine the mass of the chain.

0.082 kg

Explanation:

The center of the meter stick = 50 cm.

When a small chain is place at one end, the balance point is moved 14 cm towards the end with the chain.

The new balance point = 50-14 = 36 cm

Using the principle of moment,

Sum of clockwise moment = sum of anti clockwise moment.

W(36-0) = W'(50-36) Equation 1

Where W = weight of the chain, W' = weight of the meter stick

36W = 14W'

make W the subject of the equation

W = 14W'/36 Equation 2

Given: W' = m'g, where m' = mass of the meter stick, m' = 0.21 kg

W' = 0.21(9.8) = 2.058 N

Substitute into equation 2

W = 14(2.058)/36

W = 0.8 N

But

W = mg,

Where m =  mass of the chain.

m = W/g

m = 0.8/9.8

m = 0.082 kg.

Hence the mass of the chain = 0.082 kg

you get 2.3=1.21*\frac{a}2 or 4.6=1.21a or a=3.802 (b)

explanation: