* 39 Two blocks connected by a string are on a horizontal frictionless surface. The blocks are connected to a hanging weight by means of a string that passes over a pulley (Fig. 4-44). (a) Find the tension T in the string connecting the two blocks on the horizontal surface. (b) How much time is required for the hanging weight to fall 10.0 cm if it starts from rest? 2,00 kg T 3.00 kg Frictionless Fig. 4-44 Con ford seat ** 43 A b 2.00 the (a) C h 2 is (b) C (t 10 (c) No tha cel upp 5.00 kg

2) (a)If half of the weight of a flatbed truck is supported by its two drive wheels, what is the maximum acceleration (in m/s2) it can achieve on dry concrete where the coefficient of kinetic friction is 0.7 and the coefficient of static friction is 1.  _____ m/s2   (b) Will a metal cabinet lying on the wooden bed of the truck slip if it accelerates at this rate where the coefficient of kinetic friction is 0.3 and the coefficient of static friction is 0.55? Yes or No?      (c) If the truck has four-wheel drive, and the cabinet is wooden, what is it's maximum acceleration (in m/s2)?  _____m/s2 Will it slip? Yes or No?

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

63 N ○ 66 N A traffic light of weight 75 N is supported by two ropes as shown in Fig. 4-2. What are the tensions in the ropes? Ⓒ 50 N 37° 83 N 37° FIGURE 4-2

A 3 kg ladder is leaning on a wall. If a load P=30 N is applied vertically on the ladder as shown on figure, determine the friction forces at supports A & B when the motion impends. Use u=0.23 at A and u=0.34 at B. Figure 2-4 A 2 m 4 m 3 m

3-7. The man attempts to pull down the tree using the cable and small pulley arrangement shown. If the tension in AB is 60 lb, determine the tension in cable CAD and the angle which the cable makes at the pulley. D 20 8 30⁰

2) A cat with a mass of {04} kg is at rest on a roof at an angle of 34° from horizontal.  The coefficient of static friction between cat paws and roof tiles is 0.70, and gravity is 10 N/kg today.    a) Draw a Force Body Diagram of the cat, labelling and calculating all forces.      b) Draw a 2nd  FBD of the cat if the angle of the roof was 74° from horizontal (steeper).  Will the cat be able to stay on the roof at this angle?  Justify with calculations why or why not? c) If the coefficient of kinetic friction between cat and roof were zero, what would be the cat’s acceleration on the 74° roof?