Forces definitions

Question 1

Hooke’s law

Answer 1

The extension of a body is proportional to the applied load if the limit of proportionality is not exceeded

Question 2

Density

Answer 2

Mass per unit volume

Question 3

Pressure

Answer 3

Force per unit area

Question 4

Upthrust

Answer 4

Vertical upward force exerted on a body by a fluid when it is fully or partially submerged in the fluid due to the difference in fluid pressure

Question 5

Archimedes Principle

Answer 5

Upthrust on a body in a fluid is equal to the weight of the fluid displaced by the body

Question 6

Principle of floatation

Answer 6

For an object floating in equilibrium, the upthrust is equal in magnitude and opposite in direction to the weight of the object

Question 7

Moment of a force about an axis

Answer 7

The moment of a force about an axis is defined as the product of the force and the perpendicular distance of the line of action of the force from the axis

Question 8

Couple

Answer 8

A pair of equal and opposite forces whose lines of actions do not coincide

Question 9

Torque of a couple

Answer 9

The product of the magnitude of one of the forces and the perpendicular distance between the forces

Question 10

Centre of gravity

Answer 10

The point at which its whole weight appears to act

Question 11

Static equilibrium

Answer 11

Translation eq: The total resultant forces acting on the object must be zero;

Rotational eq / Principle of moments: For a body in rotational equilibrium, the sum of all the clockwise moments about any axis must be equal to the sum of all the anticlockwise moments about the same axis