A$.$ When the block arrives at point C $($where it comes to a stop$)$ from point B at the bottom of the hill, energy has decreased and energy has increased.Are there any external forces that transfer energy in or out of the system as work? B$.$ Use the parameters of the problem to write an expression for the change in the form of energy that has increased from B to C$.$ C$.$ The change in the form of energy that increases from B to C is the energy the block had at the top of the hill.D$.$ Write an expression for L$,$ the distance along the horizontal surface the block travels until it comes to a stop, using the other parameters of the problem.L $=$