A man holds a 164-N ball in his hand, with the forearm horizontal (see the figure). He can support the ball in this position because of the flexor muscle force M, which is applied perpendicular to the forearm. The forearm weighs 23.7 N and has a center of gravity as indicated. Find (a) the magnitude of M and the (b) magnitude and (c) direction (as a positive angle counterclockwise from horizontal) of the force applied by the upper arm bone to the forearm at the elbow joint. Upper arm bone- Elbow joint J 1 1 0.0510 mT I I M Flexor muscle- 0.0890 m 0.330 m-

Mark is trying to rescue Mary from a castle by climbing a uniform ladder that is 5 m long and weighs 180 N. Mark, who weighs 800 N, stops a third of the way up the ladder . The base of the ladder rets on a horizontal ground and leans in equilibrium against a vertical frictionless wall. The ladder makes an angle of 53.1 degrees with the horizontal, and forming a 3-4-5 right triangle. Find the force exerted by the ground at the base of the ladder.

Chapter 12, Problem 034 In the figure, a thin horizontal bar AB of negligible weight and length L = 3.1 m is hinged to a vertical wall at A and supported at B by a thin wire BC that makes an angle e = 42° with the horizontal. A block of weight W = 250 N can be moved anywhere along the bar; its position is defined by the distance x = 1.75 m from the wall to its center of mass. Find (a) the tension in the wire, and the (b) horizontal and (c) vertical components of the force on the bar from the hinge at A. Com A B (a) Number Units (b) Number Units (c) Number Units Click if you would like to Show Work for this question: Open Show Work

A man holds a 183-N ball in his hand, with the forearm horizontal (see the figure). He can support the ball in this position because of the flexor muscle force M→, which is applied perpendicular to the forearm. The forearm weighs 24.5 N and has a center of gravity as indicated. Find (a) the magnitude of M→ and the (b) magnitude and (c) direction (as a positive angle counterclockwise from horizontal) of the force applied by the upper arm bone to the forearm at the elbow joint.

Chapter 12, Problem 037 GO In the figure, a uniform plank, with a length L of 6.83 m and a weight of 386 N, rests on the ground and against a frictionless roller at the top of a wall of height h = 2.78 m. The plank remains in equilibrium for any value of e = 70.0° or more, but slips if e < 70.0°. Find the coefficient of static friction between the plank and the ground. Roller Number Units the tolerance is +/-2% Click if you would like to Show Work for this question: Open Show Work

A diver of weight 580 N stands at the end of a diving board of length L= 4.3 m and negligible mass (see the figure below). The board is fixed to two pedestals separated by distance d = 1.3 m. Take the upward direction to be positive. Of the forces acting on the board, what are (a) the force from the left pedestal and (b) the force from the right pedestal? (a) Number (b) Number 368.9 948.9 Units Units TOENE N N

A 740 N bear is standing on a metal plank supported by the cable shown in the figure. At the end of the plank hangs a basket weighing 80 N. Assume the plank is uniform, weighs 200 N, is 5.50 m long, and 0 = 60.0°. Goodies (a) When the bear is at x = 1.10 m, find the tension in the cable supporting the plank and the components of the force exerted by the wall on the left end of the plank. (Enter the magnitudes of your answers in N.) T = F = F = N N N (b) If the cable can withstand a maximum tension of 875 N, what is the maximum distance (in m) the bear can walk before the cable breaks? (Measure this distance from the wall.) m

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 man holds a 186-N ball in his hand, with the forearm horizontal (see the figure). He can support the ball in this position because of the flexor muscle force M, which is applied perpendicular to the forearm. The forearm weighs 21.6 N and has a center of gravity as indicated. Find (a) the magnitude of M and the (b) magnitude and (c) direction (as a positive angle counterclockwise from horizontal) of the force applied by the upper arm bone to the forearm at the elbow joint. (a) Number (b) Number i (c) Number i Upper arm bone- Elbow joint 0.0510 m+ Units Units Units Flexor muscle M -0.0890 m -0.330 m-

A lunch tray is being held in one hand, as the drawing illustrates. The mass of the tray itself is 0.300 kg, and its center of gravity is located at its geometrical center. On the tray is a 1.00 kg plate of food and a 0.330 kg cup of coffee. Obtain the force T exerted by the thumb and the force F exerted by the four fingers. Both forces act perpendicular to the tray, which is being held parallel to the ground.T =  N (downward)F =  N (upward)