Diagram Of A Small Sail Boat Help Me! Physics...can Get It Right - A Small Block Of Mass M = 0.50 Kg Is Fired With An Initial Speed Of...?

Help me! Physics...can get it right - A small block of mass m = 0.50 kg is fired with an initial speed of...? - diagram of a small sail boat

.... V0 = 4.3 m / s along the horizontal section of the friction of the runway, as in the top of the figure below. The mass movements along the friction semicircular, vertical lines with the radius R = 1.5 m. (Use g = 9.8 m/s2).

*** Link Graph: http://www.webassign.net/sf/p7_58.gif

(c) The lower part of the trail consists of a section (L = 0.36 m) with friction. Determine the coefficient of kinetic friction between the block and the proportion of the lower track, if the block is the fact that the point C on the first trip. [Note: If the block of the fact that the point C, the length of the contact force exerted on the block at this point will have to be zero.] ___ANSWER___?

OK, so there are three parts to this problem and found the first 2, but can not this right, the first part ... and this part must be the easiest way. Can you help me solve this problem and shows the steps used to achieve the answer. Mil gracias!