Mechanics

Question 1

Newton’s First Law

Answer 1

An object at rest remains at rest, or if in motion, remains in motion at a constant velocity, unless acted on by a net, external (resultant) force.

Question 2

Newton’s Second Law

Answer 2

The resultant force on an object is directly proportional to the rate of change of momentum of that object.

Question 3

Newton’s Third Law

Answer 3

When two objects interact, the force from this interaction acting on one object will be equal and opposite to the force from the interaction acting on the other.

Question 4

Principle of Moments

Answer 4

If an object is in rotational equilibrium, the sum of the clockwise moments about a pivot equals the sum of the anticlockwise moments around that same pivot.

Question 5

Torque/Moment (of a Force)

Answer 5

The force multiplied by the perpendicular distance of the pivot from the line of action of the force.

Question 6

Law of Conservation of Energy

Answer 6

Energy cannot be created or destroyed, only converted from one form to another.

Question 7

Translational Equilibrium

Answer 7

If an object is not experiencing linear acceleration. (It could still be rotating so could still be experiencing a resultant force which is the centripetal force)

Question 8

A Couple

Answer 8

A pair of forces which are antiparallel and equal in magnitude, which exert a resultant torque on an object but no resultant force.