Question

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.

Short answer

Answer

The metal block should be colder than the peg. The peg is made larger, and the temperature of the metal block must be less than the temperature metal peg. So if a peg is inserted into the hole and the temperature rises it gets a tight fit due to the thermal expansion of the metal block

Step-by-step solution

Thermal expansion

Thermal expansion is the tendency of a matter to change its area, shape, and volume with a temperature change.

Explanation

During the peg insertion,the metal block should be colder than the peg. Since the metal peg is made larger, therefore the temperature of the metal block should be less than the temperature of the peg so that if the peg is inserted into the hole and the temperature rises, it gets a tight fit due to the thermal expansion of the metal block.

The size of the hole reduces due to the thermal expansion of metal when the temperature rises. Therefore, at the insertion time, the temperature of the metal block should be less than the temperature of the peg.