Hello I need help with the following question please and thank you 42,45,47 and 55

42 A small block of mass m slides without friction around the loop-the-loop apparatus shown below. (a) If the block starts from rest at A, what is its speed at B? (b) What is the force of the track on the block at B? A 4R R B 3.4 Potential Chergy Diagrams and Stabity. 45. A mysterious constant force of 10 N acts horizontally on everything. The direction of the force is found to be always pointed toward a wall in a big hall. Find the potential energy of a particle due to this force when it is at a distance x from the wall, assuming the potential energy at the wall to be zero. 46. A single force F (x) = -4.0x (in newtons) acts on a 1.0-kg body. When a = 3.5 m, the speed of the body is 4.0 m/s. What is its speed at r = 2.0 m? 47 A particle of mass 4.0 kg is constrained to move along the x-axis under a single force F (x) = -cx3, where c = 8.0 N/m . The particle's speed at A, where TA = 1.0 m, is 6.0 m/s. What is its speed at B, where TB = -2.0 m? 55. In the Hunger Games movie , Katniss Everdeen fires a 0.0200-kg arrow from ground level to pierce an apple up on a stage. The spring constant of the bow is 330 N/m and she pulls the arrow back a distance of 0.55 m. The apple on the stage is 5.00 m higher than the launching point of the arrow. At what speed does the arrow (a) leave the bow? (b) strike the apple