A square hole 8.00 cm along each side is cut in a sheet of copper. Calculate the change in the area of this hole resulting when the temperature of the sheet is increased by 48.0 K.We don‘t know where to start on this.
The starting area of this circle is a(pi)r^2 , where r 4cm (or one-half of L) You need to look up, in your book most likely, the coefficient of thermal expansion for copper. It is most likely given in degrees Celsius, so make sure to convert your Kelvin temperatures, accordingly. You should also be able to identify the thermal expansion equation: the change in length of a material is equal to the initial length of the material multiplied by the coefficient of thermal expansion for the material multiplied by the change in temperature of the material. This gives you the CHANGE in the LENGTH of the material. Now, calculate the area of the circle after expansion: A (pi)R^2 , where R is equal to half of the sum of L plus the change in L: R [L + (change in L)]/2 Finally, subtract these two quantities to find your change in area: change in area: ( A - a ) pi(R^2 - r^2) pi([(L/2)^2] - [(L + change in L)/2]^2]) Love the physics.
