1. Two forces, F1 and F2, act at a point. The magnitude of F1 is 8.50 N, and its direction is an angle 65.0 above the negative direction of x-axis in the second quadrant. The magnitude of F2 is 5.00 N, and its direction is an angle 54.1 below the negative direction of x-axis in the third quadrant. a) What is the x -component of the resultant force? Express your answer in newtons. b)What is the y -component of the resultant force? Express your answer in newtons. c) What is the magnitude of the resultant force? Express your answer in newtons.

2. A 56.5 kg skater moving initially at 2.40 m/s on rough horizontal ice comes to rest uniformly in 3.52 s due to friction from the ice. a) What force does friction exert on the skater? Express your answer with the appropriate units. Enter positive value if the direction of the force is the same as that of the initial velocity of the skater and negative value if the direction of the force is opposite.

3. An astronaut's pack weighs 19.0 N when she is on earth but only 3.64 N when she is at the surface of moon. a) What is the acceleration due to gravity on this moon? Express your answer with the appropriate units. b) What is the mass of the pack on this moon? Express your answer with the appropriate units.

4. Boxes A and B are in contact on a horizontal, frictionless surface (Figure 1). Box A has mass 25.0 kg and box B has mass 4.0 kg. A horizontal force of 180 N is exerted on box A. a) What is the magnitude of the force that box A exerts on box B ? Express your answer with the appropriate units.