Consider the problem of hammering a nail into a board. With due regard for your hand holding the nail, place its pointed tip on the wood and strike it with a hammer. If the wood is hard so the nail does not go in easily, you will notice that the nail gets warm, especially after several strikes. We can figure out how much its temperature will rise by connecting what we know about Newtonian mechanics with what we are learning about temperature and heat. A 16-penny nail will have a mass of 10 g. This is the sort of nail used to build walls in a house. Strike it with one strong blow from a hammer with a mass of 0.5 kg (that's about 1 lb, so this is a good sized carpenter's hammer). Assume the impact velocity of the hammer on the head is 15 m/s and that it stops firmly at each blow. To make a reasonable assumption about the outcome, also assume that 75% of the energy of the hammer is converted into heat after the blow. The specific heat of the steel in the nail is about 482 J kg-1 K-1 . What is the temperature increase in the nail if it does not lose heat rapidly to the wood when when it was hammered?
Consider the problem of hammering a nail into a board. With due regard for your hand holding the nail, place its pointed tip on the wood and strike it with a hammer. If the wood is hard so the nail does not go in easily, you will notice that the nail gets warm, especially after several strikes. We can figure out how much its temperature will rise by connecting what we know about Newtonian mechanics with what we are learning about temperature and heat.
A 16-penny nail will have a mass of 10 g. This is the sort of nail used to build walls in a house. Strike it with one strong blow from a hammer with a mass of 0.5 kg (that's about 1 lb, so this is a good sized carpenter's hammer). Assume the impact velocity of the hammer on the head is 15 m/s and that it stops firmly at each blow.
To make a reasonable assumption about the outcome, also assume that 75% of the energy of the hammer is converted into heat after the blow. The specific heat of the steel in the nail is about 482 J kg-1 K-1 .
What is the temperature increase in the nail if it does not lose heat rapidly to the wood when when it was hammered?
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