Closure: A dog walker is trying to control three different dogs. One is pulling N72W with a force of 24 Ibs. A second is pulling S13E with a force of 40 lbs. The third is pulling S71W with a force of 34 lbs. What is the magnitude, direction angle and bearing of the force that the dog walker must apply so that she is in equilibrium?

Question 11. A person is trying to judge whether a picture (mass positioned by temporarily pressing it against a wall. The pressing force is perpendicular to the wall. The coefficient of static friction between the picture and the wall is 0.650. What is the 2.59 kg) is properly minimum amount of pressing force that must be used? Ans: 39 N Question 12 A 1

A ladder of weight W stands on a rough floor and rests against a frictionless wall, illustrated above. It is only stable if the angle between the ladder and the ground is greater than theta (theta > 60 degree). a. Find the coefficient of static friction between the floor and the ladder. b. A child of weight 4W places the ladder against the wall at angle 70 degree(theta = 70 degree). Calculate how far up the ladder it is safe for the child to climb.

The 100kg object is held by three strings as shown in the figure below (0-60°). (a) Analyze the forces on the object, find the tension force in the bottom string. N. The magnitude of the tension on the bottom string: T3 = (b) Analyze the forces exerted on the junction of the three strings, and calculate the tension forces in the left, and right strings. N. The magnitude of the tension on the left string: T1 = N. The magnitude of the tension on the right string: T2 = Click Save and Submit to save and submit. Click Save All Answers to save all answers. Save 20201124 191 20201124 191313.jpg O 20201124_191305.jpg 20201124 191320.jpg

5. Determine the force exerted by the cable at B and the reaction at support A for the bar shown. You may assume the bar is massless for the analysis. Write your answers using 3 significant digits. y A 900 N Cable B 22° C 40° 300 mm 250 mm

T, T 45° 60° 200 N The diagram shows a mass of force 200N held in place between two parallel vertical walls . A cable of tension T¡ at 45° above the horizontal is placed at one end and a second cable of tension T, at 60° above the horizontal is placed at the other end. The system is in equilibrium. Find the values of T, and T, (to the nearest whole numbers).

6. A wedge of cheese is suspended at rest by two strings which exert forces of magnitude F1 (Black) and F2 (Red), as seen below. F1 is applied at an angle of 50 degrees to the horizontal. There is also a downward force of gra on the cheese of magnitude 15N (Green). What is the magnitude of the force F1? What is the magnitude of the force F2?

If the coefficient of static friction between all surfaces in contact is µg = 0.3 and a determine force P that must be applied to wedge A in order to lift the block weighing 500 N. The weight of wedge A is negligible compared to the block. B P

GOAL Apply the concept of static friction to an object resting on an incline. PROBLEM Suppose a block with a mass of 2.50 kg is resting on a ramp. If the coefficient of static friction between the block and ramp is ng sin e 0.350, what maximum angle can the ramp make with the horizontal mg cos e e before the block starts to slip down? STRATEGY This is an application of Newton's second law involving an object in equilibrium. Choose tilted coordinates, as in the figure. Use the fact that the block is just about to slip when the force of static friction takes its maximum value, f. = 4n. SOLUTION Write Newton's laws for a static system (1) EF = mg sin e - u̟n = 0 in component form. The gravity force (2) EF = n - mg cos e = 0 has two components. Rearrange Equation (2) to get an n = mg cos 8 expression for the normal force n. Substitute the expression for n into EF, = mg sin 8 - H mgcos 0 = 0 → tan 8 =u. Equation (1) and solve for tan 0. Apply the inverse tangent function to get the answer.…

QS In what direction does the tension force always point? Q9 Why is the tension force always a pull and never a push? Q10 Tension is transmitted through a rope or cable by forces acting on both ends of the rope or cable. Why do we not identify (or give different labels to) the tension force on each end separately? Perpendicular to a Surface: Normal Force, FN Activity 4 A book resting on a table does not move. According to ewton's First Law, the net force on the book must be zero since the book is not moving. The force that explains why books do not fall through tables is called the normal force FN. It is a perpendicular contact force exerted by a surface. In the drawing at the right, a book is sitting on the table. The book is not moving, so the net force on it must be zero. FN Fg Q11 How does the table “know" how much normal force to exert as the weight of the object placed on top of it changes?