The picture shows two wood cars with metal sheets attached. One metal sheet is positively charged, the other negatively charged. The wedges prevent the cars from moving. Predict how the force between the sheets would be different if this experiment were done with twice as much charge on each of the plates. Justify your prediction.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.

they are called fossil fuels