# Homework Help: Thermal expansion of brass and iron rings

1. Apr 19, 2012

### emc92

A brass plug is to be placed in a ring made of iron. At 10°C, the diameter of the plug is 8.731 cm and that of the inside of the ring is 8.719 cm.

a) They must both be brought to what common temperature in order to fit?

b) What if the plug were iron and the ring brass?

formula for thermal expansion: Δl = $\alpha$ * l0 * ΔT

do i just equal Δl for brass and iron?

2. Apr 19, 2012

### LawrenceC

No, if each increases in diameter by the same amount, the plug will still not fit.

3. Apr 19, 2012

### LawrenceC

Hint:

The thermal expansion coefficients for brass and iron are different.