A 863-kg car starts from rest on a horizontal roadway and accelerates eastward for 5.00 s when it reaches a speed of 30.0 m/s. What is the average force exerted on the car during this time?

An object of mass m = 1.00 kg is observed to have an acceleration a with a magnitude of 10.0 m/s2 in a direction 60.0 east of north. Figure P4.29 shows a view of the object from above. The force F2 acting on the object has a magnitude of 5.00 N and is directed north. Determine the magnitude and direction of the one other horizontal force F1 acting on the object. Figure P4.29

A 75.0-g arrow, fired at a speed of 110 m/s to the left, impacts a tree, which it penetrates to a depth of 12.5 cm before coming to a stop. Assuming the force of friction exerted by the tree is constant, what are the magnitude and direction of the friction force acting on the arrow?

A block with mass m1 hangs from a rope that is extended over an ideal pulley and attached to a second block with mass m2 that sits on a ledge slanted at an angle of 20 (Fig. P5.49). Suppose the system of blocks is initially motionless and held still, and then it is released. If m1 = 7.00 kg and m2 = 2.00 kg, find the magnitude of the acceleration of the blocks, assuming there is no friction between the second block and the ledge. FIGURE P5.49 Problems 49 and 50.

The x and y coordinates of a 4.00-kg particle moving in the xy plane under the influence of a net force F are given by x = t4 6t and y = 4t2 + 1, with x and y in meters and t in seconds. What is the magnitude of the force F at t = 4.00 s?

A small sports car collides head-on with a massive truck. The greater impact force (in magnitude) acts on (a) the car, (b) the truck, (c) neither, the force is the same on both. Which vehicle undergoes the greater magnitude acceleration? (d) the car, (e) the truck, (f) the accelerations are the same.

FIGURE P5.49 Problems 49 and 50. Suppose the system of blocks in Problem 49 is initially held motionless and, when released, begins to accelerate. a. If m1 = 7.00 kg, m2 = 2.00 kg, and the magnitude of the acceleration of the blocks is 0.134 m /s2, find the magnitude of the kinetic frictional force between the second block and the ledge. b. What is the value of the coefficient of kinetic friction between the block and the ledge?

In Example 4.5, we pushed on two blocks on a table. Suppose three blocks are in contact with one another on a frictionless, horizontal surface as shown in Figure P4.49. A horizontal force F is applied to m1. Take m1 = 2.00 kg, m2 = 3.00 kg, m3 = 4.00 kg, and F = 18.0 N. (a) Draw a separate free-body diagram for each block. (b) Determine the acceleration of the blocks. (c) Find the resultant force on each block. (d) Find the magnitudes of the contact forces between the blocks. (e) You are working on a construction project. A coworker is nailing up plasterboard on one side of a light partition, and you are on the opposite side, providing backing by leaning against the wall with your back pushing on it. Every hammer blow makes your back sting. The supervisor helps you put a heavy block of wood between the wall and your back. Using the situation analyzed in parts (a) through (d) as a model, explain how this change works to make your job more comfortable. Figure P4.49

You push an object, initially at rest, across a frictionless floor with a constant force for a time interval t, resulting in a final speed of v for the object. You then repeat the experiment, but with a force that is twice as large. What time interval is now required to reach the same final speed v? (a) 4 t (b) 2 t (c) t (d) t/2 (e) t/4

The starship Enterprise has its tractor beam locked onto some valuable debris and is trying to pull it toward the ship. A Klingon battle cruiser and a Romulan warbird are also trying to recover the item by pulling the debris with their tractor beams as shown in Figure P5.25. a. Given the following magnitudes of the tractor beam forces, find the net force experienced by the debris: FEnt = 7.59 106 N, FRom = 2.53 106 N, and FKling = 8.97 105 N. b. If the debris has a mass of 2549 kg, what is the net acceleration of the debris? FIGURE P5.25