1. A 4000 kg truck coasting at a speed of 30 m/s skids to a halt on wet concrete, where k = 0.60. How long are the skid marks? 2. A 25 kg crate is sitting on a horizontal conveyor belt to be moved about a factory. The materials of the crate and belt are such that s = 0.60 and k = 0.35. a) Draw a free-body diagram showing all of the forces on the crate if the conveyor belt is moving at a constant speed. b) Draw a free-body diagram showing all of the forces on the crate if the conveyor belt is speeding up. c) What is the maximum acceleration the belt can have without the crate moving? d) If the acceleration of the belt exceeds the value determined in part c by 5 N, what is the acceleration of the crate? 3. A fish scale is made of a spring hung at one end from support. The spring's equilibrium (natural) length is 10.0 cm. When a 10 kg fish is suspended from the free end of the spring, it stretches to a length of 13.5 cm. a) What is the spring constant k for this spring? b) If a 16.5 kg fish is suspended from the spring, how far will the spring stretch? What will the final length of the spring be? 4. A spring with a spring constant is k is attached to the wall at the top of a ramp with an angle , as shown in the image below. The equilibrium length of the spring is l0. a) A box of mass m is attached to the spring, which causes the spring to stretch to some final length, l. Using m, l0, l, k, g, and , write an equation to determine how far the spring stretched (l). b) Apply this equation to determine the how far the spring stretched if the l0 = 10 cm, m = 15 kg, = 15, and k = 250 N/m.