$7.$ If you have ever been to a beach on a hot day, you may have noticed that the sand feels incredibly hot. A beach has $39500$ kg of sand which starts off at $15\backslash$deg C when the Sun first rises.By mid$-$day the sand will have absorbed $1.3\backslash$times $10\backslash$deg J of energy, raising its temperature to $55\backslash$deg C$.$What is the specific heat capacity of the sand?