Forces and Dynamics

Question 1

Normal Contact Force

Answer 1

Normal contact force is a force perpendicular to the surface experienced by a body when it is in physical contact with something else.

Question 2

Hooke’s Law

Answer 2

Hooke’s Law states that within the limit of proportionality, the extension produced in a material is directly proportional to the load applied.

Question 3

Principle of Moments

Answer 3

The principle of moments states that, when an object is in equilibrium, the sum of anticlockwise moments about any point equals the sum of clockwise moments about the same point.

Question 4

Moment of a force

Answer 4

The moment of a force is the product of the force and the perpendicular distance between the axis of rotation and the line of action of the force.

Question 5

Couple

Answer 5

A couple is a pair of forces, equal in magnitude but opposite in direction, whose lines of motion do not coincide.

Question 6

Centre of gravity

Answer 6

Centre of gravity is the point on an object through which the entire weight of the object may be considered to act.

Question 7

Stabillity

Answer 7

Stability of an object refers to its ability to return to its original position after it has been displaced from that position.

Question 8

Pressure

Answer 8

Pressure is force acting per unit area.

Question 9

Upthrust/buoyancy force

Answer 9

Upthrust/buoyancy force is an upward force on a body produced by the surrounding fluid (i.e., a liquid or a gas) in which it is fully or partially immersed, due to the pressure difference of the fluid between the top and bottom of the object.

Question 10

Archimedes’ Principle

Answer 10

Archimedes’ Principle states that the upthrust experienced by an object partially or entirely immersed in a fluid is equal to the weight of the fluid displaced by the object.

Question 11

Newton’s First law of motion

Answer 11

Newton’s first law of motion states that a body will continue in its state of rest or uniform motion in a straight line unless an external resultant force acts on it.

Question 12

Newton’s Second law of motion

Answer 12

Newton’s second law states that the rate of change of momentum of a body is proportional to the resultant force acting on it and the change takes place in the direction of the force.

Question 13

Newton’s Third law of motion

Answer 13

Newton’s third law states that: If body A exerts a force on body B, then body B exerts a force of equal magnitude but in the opposite direction on body A.

Question 14

Principle of concervation of momentum

Answer 14

The principle of conservation of momentum states that the total momentum of a system of objects remains constant provided no resultant external force acts on the system.