Reading Quiz 11 (CH 7.8-7.10, 8.4, 9.0-9.6)

Match each situation to the type of equilibrium it represents. 1. a hanging pendulum 2. a pencil balanced on its tip 3. a book sitting on a table

1. Stable equilibrium 2. Unstable equilibrium 3. Neutral equilibrium

Match the situation to the appropriate constant. 1. A tennis racket string is stretched. 2. A book on a table is pushed sideways without slipping. 3. A submarine submerges in the ocean. 4. A pillar supports an arch on a building.

1. Young's modulus 2. Sheer modulus 3. Bulk modulus 4. Young's modulus

Which of the following are necessary conditions for equilibrium in two dimensions? (Choose all that apply). - The net force in the x-direction must be zero. - The net force in the y-direction must be zero. - The net torque around any arbitrary axis must be zero.

All are true.

Hooke's law works in the elastic region and plastic region of a substance.

False

If there is a net force acting on an object then there must also be a net torque acting on the object.

False

When solving problems with static equilibrium, the best axis to use as a reference for calculating torque is an axis which has forces of known value acting on that axis.

False

To solve problems involving static equilibrium you should use - conservation of energy. - conservation of momentum. - Newton's 2nd law. - kinematic equations.

Newton's 2nd law

Which of the following is not true about the center of mass? - Some of the mass of an object must be located at is center of mass. - The center of mass of a symmetrically shaped object is at its geometric center. - The center of mass of an object will always follow a parabolic path when the object is undergoing projectile motion with no air resistance. - If a person's center of mass is exactly 2.5 feet below the person's head when they are standing up, then their center of mass may be in a different location relative to their head when they are sitting down.

Some of the mass of an object MUST be located at its center of mass

Fracture occurs when what quantity exceeds some maximum limit? - strain - stress - force - torque

Stress

A father and his pre-school daughter sit on a see-saw, each the same distance from the center pivot point. The center of mass of the system consisting of father, daughter, and see-saw is - at the pivot point. - closer to the daughter than the father. - closer to the father than the daughter. - can not be determined with the information given.

closer to the father than the daughter

A wrench with a long handle can provide more torque than a wrench with a short handle because it has a longer lever arm.

true