1. Several forces act on an object at rest. It is known that thesum of the forces acting on the object is zero. Which statement isnecessarily true?
A) The object will remain stationary.
B) The object's center of mass may move in such a way that theobject will roll without slipping.
C) The object's center of mass will not move, but the object maybegin to rotate.
D) The object's center of mass may accelerate and the object maybegin to rotate.
E) The object's center of mass may accelerate, but the object willremain in the same orientation.

2. A heavy boy and a lightweight girl are balanced on a masslessseesaw. If they both move forward so that they are one-half theiroriginal distance from the pivot point, what will happen to theseesaw?
A) It is impossible to say without knowing the masses.
B) It is impossible to say without knowing the distances.
C) The side the boy is sitting on will tilt downward.
D) Nothing, the seesaw will still be balanced.
E) The side the girl is sitting on will tilt downward.

3. A cone balanced on its small end is in
A) stable equilibrium.
B) unstable equilibrium.
C) neutral equilibrium.
D) positive equilibrium.
E) negative equilibrium.

4. A sphere hanging freely from a cord is in
A) stable equilibrium.
B) unstable equilibrium.
C) neutral equilibrium.
D) positive equilibrium.
E) negative equilibrium.

5. The region from the origin to the elastic limit on an appliedforce versus elongation graph for a typical metal under tension isreferred to as the
A) elastic region.
B) proportional region.
C) plastic region.
D) ultimate strength region.
E) breaking region.

6. The maximum elongation of a typical metal is reached atthe
A) proportional limit.
B) elastic limit.
C) inelastic limit.
D) breaking point.
E) ultimate strength.

7. Strain is
A) the ratio of the change in length to the original length.
B) the stress per unit area.
C) the same as force.
D) the applied force per cross-sectional area.
E) the ratio of stress to elastic modulus.