The weightless strut in the figure below is not attached to the wall; it is prevented from falling only by friction. (Let w = 365 N, L = 4.45 m and h = 2.95 m.)   (a) Find the magnitude of the force of friction between the wall and the strut. (b) Find the normal force exerted by the wall on the strut. (c) Find the minimum coefficient of static friction.

6. A uniform ladder 10.0 m long is leaning against a frictionless wall at an angle of 60.0° above the horizontal. The weight of the ladder is 50.0 N. A 150.0 N boy climbs 4.00 m up the ladder. What is the magnitude of the frictional force exerted on the ladder by the floor?

You are working in an ice skating rink and have been asked to hang a new banner on the wall. Your friend is helping you so that the ladder does not collapse by exerting a force F_AL at an angle ϕ relative to the horizontal. The ladder has a length L and makes an angle of θ with respect to the vertical wall. You have a mass, m_Y, and are a horizontal distance x from the wall. The ladder has a mass of m_L. Because the wall is slick, and the ice on the floor is slick, the frictional forces acting on the ladder are negligible. Find a formula for the magnitude of the force that your friend must exert to keep the ladder from falling, in terms of the following variables: x,L,m_Y,m_L,θ,ϕ. Then use the following values to get a number for the magnitude of F_AL.   θ = 30.3 degrees ϕ = 23.028 degrees x = 1.491 meters L = 7.1 meters m_Y = 86.0 kg m_L = 42.14 kg Find the magnitudes of: F_AL, normal force of the wall on the ladder (N_WL), and normal force of the floor on the ladder (N_FL).

A 16.0-m uniform ladder weighing 510 N rests against a frictionless wall. The ladder makes a 57.0° angle with the horizontal. (a) Find the horizontal and vertical forces the ground exerts on the base of the ladder when an 850-N firefighter has climbed 3.90 m along the ladder from the bottom. Horizontal force: magnitude direction Vertical force: magnitude direction towards the wall up N ✓✓ N (b) If the ladder is just on the verge of slipping when the firefighter is 8.70 m from the bottom, what is the coefficient of static friction between ladder and ground?

A uniform board is leaning against a smooth vertical wall. The board is at an angle  above the horizontal ground. The coefficient of static friction between the ground and the lower end of the board is 0.890. Find the smallest value for the angle , such that the lower end of the board does not slide along the ground.

The human mandible (lower jaw) is attached to the temporomandibular joint (TMJ). The masseter muscle is responsible for pulling the mandible upward when you are talking or eating. It is attached at a horizontal distance of about 2.70 cm from the TMJ. The horizontal distance from the TMJ to your incisors is 6.60 cm. If the masseter muscle exerts a force of 182 N on your mandible when you bite into an apple at a constant rate, then what is the magnitude of the force exerted by your incisors on your food, assuming that both forces are vertical?

One end of a uniform 4.40-m-long rod of weight F is supported by a cable at an angle of 0 = 37° with the rod. The other end rests against the wall, where it is held by friction as shown in the figure below. The coefficient of static friction between the wall and the rod is μ = 0.465. Determine the minimum distance x from point A at which an additional object, also with the same weight F, can be hung without causing the rod to slip at point A. A 0 B X You will need to work with the equations F net = 0 and 7 = 0 and manipulate the equations symbolically to solve for the distance. m net

A 14.0 m uniform ladder weighing 520 N rests against a frictionless wall. The ladder makes a 65.0°-angle with the horizontal. (a) Find the horizontal and vertical forces (in N) the ground exerts on the base of the ladder when an 850-N firefighter has climbed 3.80 m along the ladder from the bottom. horizontal force magnitude direction N towards the wall vertical force magnitude direction up N (b) If the ladder is just on the verge of slipping when the firefighter is 9.40 m from the bottom, what is the coefficient of static friction between ladder and ground? (c) What If? If oil is spilled on the ground, causing the coefficient of static friction to drop to half the value found in part (b), what is the maximum distance (in m) the firefighter can climb along the ladder from the bottom before the ladder slips? m

A wrecking ball (weight = 5670 N) is supported by a boom, which may be assumed to be uniform and has a weight of 2760 N. As the drawing shows, a support cable runs from the top of the boom to the tractor. The angle between the support cable and the horizontal is 32°, and the angle between the boom and the horizontal is 48°. Find (a) the tension in the support cable and (b) the magnitude of the force exerted on the lower end of the boom by the hinge at point P. (a) Number (b) Number Mk Support, cable Units Units N N 48 Boom

Determine the force P required to force the 18° wedge under the 75-kg uniform crate which rests against the small stop at A. The coefficient of friction for all surfaces is 0.38. P 8° Answer: P = 18° 356 1.4 m 75 kg 0.5 m A 18° N