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Q1:  Imagine a very simple (but inaccurate) model of a leg in which the lower leg is held in an extended position by a single muscle as shown below

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Q1: 

Imagine a very simple (but inaccurate) model of a leg in which the lower leg is held in an extended position by a single muscle as shown below. In that position for this model, the muscle makes an angle of 150 from the horizontal (directed up from the lower leg toward the knee as shown with the blue arrow) and anchors to the leg about 17 cm from the knee joint. Assume the lower leg has a mass of 17 kg and its center of mass is about 38 cm from the knee joint.

How much force does the muscle need to exert in order to support the lower leg in this position?

Q2: 

You are moving your furniture to a new apartment. When you are driving your pick-up truck at a constant speed up a hill that is inclined 180 above the horizontal, you notice the dresser in the back of your truck just about to slide. In other words, friction is barely holding the dresser in place on the truck. You panic and slam on your brakes, skidding (sliding) to a stop in 3.2 s. The mass of your truck is 2,000 kg and the mass of the dresser is 32 kg. The coefficient of kinetic friction between rubber and asphalt is about 0.60.

a. What physics approach will you use to approach part c of this problem? In one sentence, tell me a problem-specific reason that you chose this approach?

b. Draw a carefully labeled, ready to use Free Body Diagram of the dresser as you were taught in class.

c. What is the coefficient of static friction between the dresser and the bed of your truck?

d. What is the frictional force on your truck during the time you skid to a stop? It is fine to treat the dresser and truck as a single object for this question.

e. How fast were you going when you slammed on the brakes?