Question

One method of getting a tight fit, say of a metal peg in a hole in a metal block, is to manufacture the peg slightly larger than the hole. The peg is then inserted when at a different temperature than the block. Should the block be hotter or colder than the peg during insertion? Explain your answer.

a) The block should be hotter than the peg.
b) The block should be colder than the peg.
c) Temperature does not affect the fit.
d) The block and peg should be at the same temperature.

Answer 1

To fit a larger peg into a hole in a metal block, the block should be hotter than the peg during insertion. The heat will make the block expand, allowing the peg to fit, and upon cooling, the hole will shrink back, securing the peg.

Step-by-step explanation:

To achieve a tight fit of a slightly larger metal peg into a hole in a metal block, it helps to understand how temperature affects the size of materials due to thermal expansion. When a material is heated, it expands, and when it's cooled, it contracts. Therefore, the block should be hotter than the peg during insertion.

The increased temperature of the block will cause it to expand, making the hole temporarily larger, thereby allowing the initially larger peg to fit in. Once the temperatures of the peg and block equalize, the hole will contract around the peg, securing it in place.