A person carries a plank of wood 2.00 m long with one hand pushing down on it at one end with a force F 1 and the other hand holding it up at 38.0 cm from the end of the plank with force F 2. If the plank has a mass of 18.0 kg and its center of gravity is at the middle of the plank, what are the magnitudes of the forces F 1 and F 2? Part 1 What is the magnitude of F 1? Part 2 What is the magnitude of F 2?

In exercise physiology studies, it is sometimes important to determine the location of a person's center of mass. This determination can be done with the arrangement shown in the figure below. A light plank rests on two scales, which read F, = 395 N and F, gi = 340 N. A distance of 1.65 m separates the scales. How far from the woman's feet is her center of mass? g2 1.65 m F 18. F 82

The two ends of the dumbbell shown below are made of the same material. Is the dumbbell’s center of gravity at point 1, 2, or 3? Explain.

1 A person exercises the quadriceps as shown. The diagram on the right shows a model of the leg, where the person's lower leg of length L = 0.60 m is held at an angle 0₁ = 60° with respect to the horizontal. The quadriceps muscle exerts a force FM via the tendon that attaches to the tibia at a distance d = 0.10 m from the knee, in order to lift a weight of mass m₁ = 5.91 kg that is attached to the foot. The tendon makes an angle of 0₂ = 11.5° with respect to the tibia. 2 What is the force required to hold the weight at the position shown in the diagram? Assume the person's lower leg weighs 150 N and its centre of mass is located at a distance L/2 from the knee. Round your answer to the nearest Newton. FM M d- 02 01 m₁

When you bend over, a series of large muscles, the erector spinae, pull on your spine to hold you up. Figure shows a simplified model of the spine as a rod of length L that pivots at its lower end. In this model, the center of gravity of the 320 N weight of the upper torso is at the center of the spine. The 160 N weight of the head and arms acts at the top of the spine. The erector spinae muscles are modeled as a single muscle that acts at an 12° angle to the spine. Suppose the person shown bends over to an angle of 30° from the horizontal. a. What is the tension in the erector muscle? Hint: Align your x-axis with the axis of the spine.b. A force from the pelvic girdle acts on the base of the spine. What is the component of this force in the direction of the spine? (This large force is the cause of many back injuries).

1. ch A uniform 40.0-kg scaffold of length 6 m is supported by two light cables, as shown below. An 80 kg painter stands 1 m from the left end of the scaffold, and his painting equipment is 1.5 m from the right end. The tension in the left cable is twice that in the right cable. Find 1. The tension in the left cable = 2. The tension in the right cable = 3. The mass of the equipment = N 99+ N kg Think & Prepare 1. If the plank is in equilbrium, torque about any point will be zero. Pick a point about which to calculate torques. 2. Draw all forces and torques. 3. Write down the First Condition for Equilibrium symbolically. 4. Write down the Second Condition for Equilibrium symbolically. 5. How many unknowns are there? How many equations are there? 6. How can you solve the equations find the unkowns?

In exercise physiology studies, it is sometimes important to determine the location of a person's center of gravity. This can be done with the arrangement shown in the figure below. 2.00 m A light plank rests on two scales that read F = 380 N and F = 280 N. The scales are separated by a distance of 2.00 m. How far from the woman's feet is her center of gravity? Need Help? Read It

A uniform barbell has length 1.5 m and mass 60 kg. Your left hand is placed 25 cm to the left of the center, while your right hand is placed 35 cm to the right of the center. What is the magnitude of force exerted by your left hand? 420 N 823 N 343 N 294 N 245 N

Three identical coins lie on three corners of a square a = 11.0 cm on a side, as shown in (Figure 1). Determine the x coordinate of the center of gravity of the three coins. Express your answer with the appropriate units. Determine the y coordinate of the center of gravity of the three coins. Express your answer with the appropriate units.

B1