1. A 31 g ice cube at its melting point is dropped into an insulated container of liquid nitrogen. How much nitrogen evaporates if it is at its boiling point of 77 K and has a latent heat of vaporization of 200 kJ/kg? Suppose for simplicity that the specific heat of ice is a constant and is equal to its value near its melting point.
2. The 1.25 kg head of a hammer has a speed of 8.2 m/s just before it strikes a nail (Fig. 14-17) and is brought to rest. Estimate the temperature rise of a 16 g iron nail generated by ten such hammer blows done in quick succession. Suppose the nail absorbs all the energy.