A bear sling, Fig. 4–40, is used in some national parks for placing backpackers' food out of the reach of bears. As the backpacker raises the pack by pulling down on the rope, the force F needed: (a) decreases as the pack rises until the rope is straight across. (b) doesn't change. (c) increases until the rope is straight. (d) increases but the rope always sags where the pack hangs. F FIGURE 4–40 MisConceptual Question 4.

IS A) 171 N (B)262 N C) 387 N D) 398 N Do only two 16 – 18 only. 16)A 30.0-kg block is being pulled up a 25.0° slope by a force of 575 N which is parallel to the slope, but the block does not slide up the slope. What is the minimum value of the coefficient of static friction required for this to happen? | us = 575-30 x 9.8 Sin25° + Ox cos cOsZ %3D 9860 eSこ 7.51

A truck is traveling horizontally to the right (Fig. 4–-38). When the truck starts to slow down, the crate on the (frictionless) truck bed starts to slide. In what direction could the net force be on the crate? (a) No direction. The net force is zero. (b) Straight down (because of gravity). (c) Straight up (the normal force). (d) Horizontal and to the right. (e) Horizontal and to the left. FIGURE 4–38 MisConceptual Question 1.

11. (II) A 20.0-kg box rests on a table. (a) What is the weight of the box and the normal force acting on it? (b) A 10.0-kg box is placed on top of the 20.0-kg box, as shown in Fig. 4–43. Determine the normal force that the table exerts on the 20.0-kg box and the normal force that the 20.0-kg box exerts on the 10.0-kg box. 10.0 kg 20.0 kg FIGURE 4–43 Problem 11.

5. (II) A 20.0-kg box rests on a table. (a) What is the weight of the box and the normal force acting on it? (b) A 10.0-kg box is placed on top of the 20.0-kg box, as shown in Fig. 4-38. Determine the normal force that the table exerts on the 20.0-kg box and the normal force that the 20.0-kg box exerts on the 10.0-kg box. 10.0 kg 20.0 kg FIGURE 4-38 Problem 5.

2) Dallas is on her ATV when she gets stuck in the mud. The only way she can get out is if a helicopter gives it a pull. With one side of the rope secured around a tree, determine the tension P in the rope needed to pull Dallas' ATV up the incline at an acceleration of 3 ft/s?. Assume that both angles are equal to e = 30°, the weight of the ATV is 500 Ib, and the kinetic coefficient of friction between the ATV and the ground is 0.30. %3D P Hx = 0.3

The mass of a car is 1000 kg. The total opposing force for the moving car is 10 % of theweight of the car. Calculate the net force needed to move the car, if it is movingwith constant speed a) on a flat road, b) upwards on an incline of 5 °.with acceleration of 2.0 m/s2 on c) a flat road, d) downwards on an incline of 5 °.

(II) Figure 4–45 shows a block (mass ma) on a smooth hori- zontal surface, connected by a thin cord that passes over a pulley to a second block (mB), which hangs vertically. (a) Draw a free-body diagram for each block, showing the force of gravity on each, the force (tension) exerted by the cord, and any normal force. (b) Apply Newton's second law to find formulas for the acceleration of the system and for the tension in the cord. Ignore friction and the masses of the pulley and cord. FIGURE 4-45 Problems 51, 52, and 53. Mass m rests on a smooth horizontal surface, mg hangs vertically. mg

Soru 6 190 An object of mass m-0.5 kg is suspended from the ceiling of an accelerating truck as shown in the figure. A) Taking a=3 m/s², find the angle 0 that the string makes with the vertical. B) Find the tension T in the string.

A box rests on the (frictionless) bed of a truck. The truck driver starts the truck and accelerates forward. The box immediately starts to slide toward the rear of the truck bed. Discuss the motion of the box, in terms of Newton's laws, as seen (a) by Mary standing on the ground beside the truck, and (b) by Chris who is riding on the truck (Fig. 4–35). FIGURE 4-35 a Question 2. Воx