The 1.19 kg head of a hammer has a speed of 8.4 m/s just before it strikes a nail (Fig. 14-13) and is brought to rest. Estimate the temperature rise of a 13 g iron nail generated by twenty such hammer blows done in quick succession. Assume the nail absorbs all the energy.

The temperature rise is .

Explanation:

Given the mass of the hammer is 1.19 kg.

And the speed of the hammer is 8.4 m/s.

We need to find the temperature change of iron nail having 20 hammer blows.

First, we will find the kinetic energy of the each blow of hammer.

For 20 such blows, the kinetic energy will be

Let us assume that the nail absorbs all the kinetic energy. So, this 839.8 J will be converted into heat energy .

Now,

Also, we know that

Where,

is the mass of the nail, which is

is the specific heat capacity of iron, which is 449 J/kg.K

is the change in temperature.

Plug these value we get,

We can see the temperature rise is 143.9 K.

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