Show all work. All angles given are from horizontal.

1. A 10 kg wagon is pulled horizontally with a horizontal force of 20 N. There is a friction force of 5 N. Starting at rest, it is pulled for 6 s, then the 20 N is removed but the 5 N remains. Find the total distance traveled from the start to the point where it stops. Sketch a graph of v vs t well beyond 6 s.

2. A ball is thrown with V_o = 6 m/s @ 30 degrees from a 5 m height. Find x where it hits the ground.

3. A box of mass m is pulled with force F at angle q . The coefficient of kinetic friction between box and floor is m . Find the acceleration in terms of F, m , m, g, q . If you know calculus, find the angle at which acceleration is a maximum.

4. A block of mass m is on a glider of mass M on a level air track (no friction between glider and air track). There is friction between the block and the glider; the coefficient of kinetic friction is m . Force f is applied to the block such that it slides on the glider. Find both of their velocities after it has slid a distance d relative to the glider.

5. Mass m is tied to a string and swung around in a vertical circle in such a way that its total energy is constant. F is the tension when m is at the bottom, and f is the tension when m is at the top. Show that F - f = 6mg.

6. A block of wood is on a plank 3 meters long inclined at an angle of 30°. The coefficient of kinetic friction is 0.2. If it starts with v = 0 at the top, find a) the time it takes to reach the bottom and b) the heat generated while it is on the incline.

7. A 2 kg cat jumps straight up and snares a 1.5 kg pheasant which was traveling horizontally @ 10 m/s, 1.4 m above ground. When and where do they hit the ground? State any assumptions you need to make about this problem.

8. A 20 kg child is coasting at 3 m/s in a 10 kg wagon. He jumps off the front with v = 2 m/s relative to the wagon's final v. Find the final velocities of both, relative to the ground.

9. Write the conservation of energy equation for this situation: a roller coaster of mass m has speed v_o at the top of a hill of height y. On the way down, the absolute value of the work done by drag forces is W_f. The speed at the bottom is v.

10. A 2 meter long rod is hinged at the lower end. It is tilted at an angle of 60 degrees and released. a) Find the initial angular acceleration. The inertia of a rod about its end is (1/3)ml². Remember that to calculate torque, it is as if all weight is concentrated at the center of gravity. b) Find the angular speed when the rod is horizontal, using an energy approach. c) Why can't you use the rotational analogue of V² = V_o² + 2ax, i.e., w ² = w _o² + 2 a q ?

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