Calf muscle Lower leg bones B A C d AB A- dBC Ꮎ B The top left figure shows an anatomical structure in the lower leg and foot that are involved in standing on tiptoe, with the heel raised slightly off the floor so that the foot effectively contacts the floor only at point C. The calf muscle pulls on the foot at point A, which is rotating around point B where the foot contacts the lower leg bones. We want to compute the pulling force FA of the calf muscle necessary for the person to stand on tiptoe as well as the force FB on the lower leg bones from the foot. For simplicity we will assume that the points A, B and C lie on a single line as shown on the simplified diagram on the right. Assume distance dAB = 5.00 cm, distance dBC = 15.0 cm, the angle between the floor and the foot is 0 = 10.0°, and the person's mass m = 80.0 kg. We will neglect the weight of the foot. a) Draw a diagram showing the forces acting on the foot. (1 point) b) Assuming rotational equilibrium compute the calf pulling force FA. Compare the ratio of this force to the one of the person weight. Does this force depend on the angle 0? (2 points) c) Assuming translational equilibrium compute the force FB on the lower leg bones. Compare the ratio of this force to the one of the person weight. (2 points)

Q2) Machine Curls and the Biceps Muscle. A woman performs seated machine curls to strengthen her biceps muscles (the figure below). She uses a weight of 10 kg. Horizontal distance between her elbows (A) and the bottom of the frictionless pulley (B) is 60 cm. Vertical distance between the same points is 20 cm. Determine the force exerted by the holding bar on the woman's hands when her arm is at 45° with the horizontal. At that moment, the weight has an upward acceleration of 3 m/s2. DB DIA 32cm 20cm PAB 45 60cm

A 50 kgkg woman stands on a very light, rigid board that rests on a bathroom scale at each end, as shown in figure.(Figure 1) a. What is the reading on each of the scales? On the left scale Express your answer using two significant figures.   b. On the right scale. Express your answer using two significant figures.

A 40 kg, 5.0-m-long beam is supported by, but not attached to, the two posts A and B in the figure. A 20 kg boy starts walking along the beam and stops 1.2 m from the right end of the beam. The beam does not tip. A B 3.0 m a) Draw a fully labelled force diagram for the beam. b) Calculate the magnitude of the force exerted by the post B on the beam.

TEXT ANSWER Question 22 When Jenny couldn't lift a box by herself, she decided to use a lever to move it. She placed a fulcrum 1.6 m away from the box and used a 2.0 m lever to try to lift the box. Her effort was still unsuccessful. Explain why Jenny was unable to lift the box with her lever, and sug- gest a way she can adjust the lever to improve her chances of success. Use math to support your answer.

200 kg A uniform vertical rod, mass 100,0 kg, is attached at point A by means of a hinge to the ceiling of a shed as shown in the diagram. A system containing a pulley is now used to hold a mass of 200,0 kg. The tension in the horizontal part of the rope (on the right) is equal to: Select one: O a. 490,0 N O b. 1225 N 60⁰ O c. 980,0 N O d. 3430 N O e 1470 N Fi

To loosen the id on a jar of jam 7.6 cm in diameter, a torque of 14 N-m must be applied to the circumference of the lid. Part A If a jar wrench whose handle extends 14 cm from the center of the jar is attached to the lid, what is the minimum force required to open the jar? Express your answer using two significant figures. 17 ΑΣΦΑ F- ? N

10⁰ 10° An absolute unit of squirrel, 2.27 kg, walks out onto a cable and it deforms, as shown above. What is the tension?

The cylinder and the block are connected by a horizontal cord. Determine the largest couple C (in N-m) that can be applied to the cylinder without disturbing the equilibrium of the system. Assume that both bodies are homogeneous. *Write your answer in two decimal places. 3m C. 68 kg 5 m 68 kg H= 3D0.28-

3 S A 0.102 kg remote control 24.0 cm long rests on a table, as shown in the figure(Figure 1), with a length L overhanging its edge. To operate the power button on this remote requires a force of 0.360 N Figure www www 3 T MAR 27 E R F 1 of 1 5 T 6 T B G Search or type URL Part A How far can the remote control extend beyond the edge of the table and still not tip over when you press the power button? Assume the mass of the remote is distributed uniformly, and that the power button is 1.41 cm from the overhanging end of the remote. Y L= Submit Provide Feedback H MacBook Pro —| ΑΣΦ alt S & 7 N X Incorrect; Try Again; 5 attempts remaining Review your calculations and make sure you round to 3 significant figures in the last step. Previous Answers Request Answer U ☆ *00 6 8 J e I 3 - 0 S tv A 9 K F - delete