[خلف الجميلي]

A 5.0 Kg block is released from point A in the figure below. It travels along the smooth surface A  E except for the part B  C where the surface is rough. Point A is 3 m above the lowest point C. The block continues in its motion up the surface until reaches point D (1.5 m above C) where it starts compressing the spring until it comes momentarily to rest at point E (Δx above point D). The speed of the block at point C is 6 m/s.
a) calculate the energy lost due to friction in the part B  C;
b) if the spring constant kspring = 340 N/m, calculate the distance (Δx) by which the mass compresses the spring just before it comes to rest momentarily.