Chapter 6
1. (p.174 prob.7) What it the minimum work needed to push a 1000-kg car 300m up a 17.5° incline? (a) ignore friction. (b) Assume the effective coefficient of friction is 0.25.
2. (p.175 prob.22) An 80-g arrow is fired from a bow whose string exerts and average force of 95N on the arrow over a distance of 80cm. what is the speed of the arrow as it leaves the bow?
3. (176 prob.33) A 55-kg hiker starts at an elevation of 1600m and climbs to the top of a 3100-m peak. (a) What is the hiker's change in potential energy? 9b) What is the minimum work required of the hiker? (c) Can the actual work done be more than this? Explain.
4. (p.176 prob.42) A 60-kg bungee jumper jumps from a bridge. she is tied to a 12-m-long bungee cord and falls a total of 31m. (a) Calculate the spring constant k of the bungee cord. (b) Calculate the maximum acceleration experienced by the jumper.
5. (p.177 prob.51) A ski starts from rest and slides down a 20° incline 100m long. 9a) If the coefficient of friction is 0.090, what is the ski's speed at the base of the incline? (b) If the snow is level at the foot of the incline and has the same coefficient of friction, how far will the ski travel along the level? Use energy methods.
6. (p.178 prob.64) A shot-putter accelerates a 7.3-kg shot from rest to 14m/s. If this motion takes 2.0s, what average power was developed?