9.1 Conditions for Equilibrium

1

• 9.1 Conditions for Equilibrium
• SF 0 and St 0
• The axis of rotation is arbitrary
• Try to select the axis so that one torque is zero

2

• 9.1 Conditions for Equilibrium

3

• 9.2 Statics Problems
• FA should point down.
• Why?
• Which point do I use to calculate St?

4

• 9.3 Muscles and Joints

5

• 9.3 Muscles and Joints

6

• 9.5 Elasticity
• Hookes Law
• F k ?L
• Youngs Modulus

7

• 9.5 Elasticity
• Stress Strain
• Shear Modulus

8

• 9.5 Elasticity
• Bulk Modulus

9

• 9.5 Elasticity

10

• In class Problems 10, 43
• Other problems ?

8. Let m be the mass of the beam, and M be the
mass of the piano. Calculate torques about the
left end of the beam, with counterclockwise
torques positive.

11

The forces on the supports are equal in magnitude
and opposite in direction to the above two
results.