Dynamics

Question 1

Define linear momentum.

Answer 1

Linear momentum is defined as the product of a body’s mass and its linear velocity.
p = mv

Question 2

State Newton’s First Law of motion.

Answer 2

A body will stay at rest or continue to move at a constant velocity in a straight line unless acted upon by a net external force.

Question 3

State Newton’s Second Law of motion.

Answer 3

The rate of change of linear momentum of a body is directly proportional to the resultant force acting on it and is in the direction of the resultant force.
F = ma

Question 4

State Newton’s Third Law of motion.

Answer 4

If body A exerts a force on body B, then body B will exert an equal and opposite force on body
A.

Question 5

Define impulse.

Answer 5

The impulse of a force is the product of the average force and the time interval over which it is applied. Alternatively the change in momentum.
J = Favg * ΔT

Question 6

State the principle of conservation of linear momentum.

Answer 6

It states that the total momentum of a system is constant provided no net external force exerts
on it.

Question 7

Define inertia.

Answer 7

Inertia is the tendency of a body to maintain its current

motion or lack thereof unless acted upon a force.

Question 8

What is an action reaction pair?

Answer 8

Action Reaction Paris are pairs of forces which arise
due to Newton’s Third Law of Motion which then are of the same type and act upon different bodies, are equal in magnitude but opposite in direction.
Example: Normal Contact with Normal Contact, Friction with Friction, Electric with Electric

Question 9

Define elastic collisions between 2 objects.

Answer 9

Elastic collisions maintain the property of conservation

of momentum as well as conservation of kinetic energy