The car at 60 kph has 9 times more kinetic energy than the car traveling at 20 kph. This assumes that both cars have the same mass. Kinetic energy depends on the square of thee speed so if one car is going 3 times faster, its kinetic energy will be 3^2 ( = 9 ) greater. The car going at 60 kph will have 4 times the KE of the car going at 30 kph ( again assuming that the cars have the same mass.)
<span>No. Solids can't undergo convection, the reason is that convection works because moving molecules which are hotter and faster have a lower density and therefore rise to the surface. With a solid now, the molecules don't move they can only vibrate.
Therefore solids conduct.</span>
