Forces

Question 1

Define Hooke’s law

Answer 1

Hooke’s law states that the magnitude tension exerted by a spring on a body attached to a spring is proportional to the extension x of the spring from equilibrium, provided the limit of proportionality of the spring is not exceeded. F=kx

Question 2

Define moment of a force

Answer 2

Moment of a force about a point is the turning effect of the force about that point and is equal to the product of the perpendicular distance from its line of action to the point and the force.

Question 2

Define a couple

Answer 2

A couple is a pair of force of equal magnitude but opposite in direction acting on an object where their lines of action do not coincide, producing only rotation.

Question 2

Define torque of a couple

Answer 2

Torque of a couple is the product of one of the forces and the perpendicular distance between the lines of action of the forces. Torque of couple = Fd

Question 3

Define equilibrium of a body

Answer 3

Equilibrium of a body occurs when there is no resultant force in any direction and there is no resultant torque about any point.

Question 4

Define rotational equilibrium

Answer 4

Principle of moments states that for an object to be in rotational equilibrium, the sum of anti-clockwise moments about any pivot must be equal to the sum of clockwise moments about that same pivot.

Question 5

Define Archimedes’ Principle

Answer 5

Archimedes Principle states that the upthrust acting on a body, partially or totally submerged in a fluid is equal in magnitude and opposite in direction to the weight of the fluid displaced by the body. u=pvg

Question 6

Define Law of Flotation

Answer 6

Law of flotation states that the weight of the fluid displaced by an object is equal to the weight of that object when the object floats in equilibrium. upthrust = weight of object