An unbalanced force of 20N acts on a 4.0kg mass what is it's acceleration

If the temperature were raised very high, classically what would we expect the heat capacity per object to be for this one-dimensional system? give a numerical value. chigh t = __ j/k/object (one reason for the discrepancy is that the high-temperature limit assumes that the number of oscillators is large (n > > 1), which is not the case in this tiny system.)

What is the coefficient of kinetic friction μk between the block and the tabletop?

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.