From Table 9-1 on page 216 of the book, the specific heat of water is 4186 . These units assume that the temperature difference is calculated in Kelvin. However, even though temperatures in Kelvin and Centigrade are not the same, the difference between two temepratures whether calculated in Centigrade or in Kelvin are the same. Thus we may use the temperature difference we just calculated in Centigrade. The heat required is Joules or 16744 Joules.
Density is defined as the ratio of mass to volume.
To convert this to we have to multiply by 1000, giving 2700 . The length refers to the original length, before the temperature changes, in this case 1m as it is a meter stick. The change in length is negative, because the rod shrinks when the temperature falls. Now that we know the change in length, it is easy to calculate the change in temperature using the formula and the value of above. The change in temperature is found to be - .