13. A 1.00 kg block is set into motion up an inclined plane with an initial speed of 8.00 m/s. The block comes to rest after traveling 2.50 m along the plane as shown in the figure. Determine (a) the change in the potential energy of the block. (b) The change in the kinetic energy of the block. (c) The work done by friction on the block. 14. An object of mass 5.2 kg is at rest on an inclined plane as shown in the diagram below. 8.7 ma (a) What is its potential energy? (b) If the object is released from rest and slides down the inclined plane, what is its speed at the bottom? (c) If the plane was rough, and the object reaches the bottom of the plane with v = 5.5 m/'s, how much work was done by friction? 15. Christine runs forward with her sled at 2.0 m/s. She hops onto the sled at the top of a 5.0-m -high, very slippery slope. What is her speed at the bottom? 16. A dart gun with a spring constant k = 400.0 N/m is compressed 8.0 cm. (a) How much energy will it transfer to a dart of mass 200 g when the spring is released?(b) What would be the escape speed of the dart? (c) If the dart was aimed upward, how high would it travel? 17. A spring-loaded gun shoots a plastic ball with a speed of 4 m/'s. If the spring is compressed twice as far, determine what the ball's speed will be. 18. A small child slides down the four frictionless slides A-D. Each has the same height. Rank in order, from largest to smallest, her speeds ya to up at the bottom. (A) VC> VA VA>VR (B) XC >VA VA >VR (C) >VA >V XC (D)VA VA VA ER (E) VR >VA VA>VC C D 19. A particle moves along the x-axis with the potential energy shown. The force on the particle when it is at x = 4 m is 20. A particle moving along the x-axis experiences a force shown in the graph. If the particle has 2.0 J of kinetic energy as it passes x - 0 m, what is its kinetic energy when it reaches x = 4.0 m? F, (N) 2 - -x (m)