A block of mass m is pressed against a spring with constant k and held in place with a latch, as seen in the figure below. When the latch is released, the block is launched along the track. The grey parts (A to B and C to E) are all frictionless; the brown-red part (B to C) has some coefficient of kinetic friction, μ. When the block reaches point D, it slides up the ramp to point E, reaching a height h above the flat surface of the track. It then slides back down and gets all the way to point B again before coming to a stop.

) Write an expression that represents the work done by the friction force as the block passes from B to C (first pass across that section), using the variables defined in the figure, as well as g if needed. Explain your reasoning.
B) Write an expression for the potential energy of the block at point E, using the variables defined in the figure, as well as g if needed. Explain your reasoning.
C) Write an expression for the total work done by the friction force throughout the whole motion, using the variables defined in the figure, as well as g if needed. Explain your reasoning.
D) Write an expression for the total mechanical energy of the block, just before the latch is lifted. Use only variables that are defined in the figure, as well as g if needed. Explain your reasoning.
E) Write an expression for the coefficient of friction, μ, using only the variables defined in the figure, as well as g if needed. If you can’t do this without more information than is provided in the figure, explain what it is and why you can’t write the expression without it.
F) Let’s assume the following values: m=75 g, k=15 N/m, d1 = 10 cm, d2 = 10 cm, d3 = 8 cm, L = 25 cm, and θ = 20°. Using these values, calculate the coefficient of friction, μ. (Yes, it can be done!)