Chap 3: Dynamics

Question 1

Newton’s First Law:

Answer 1

A body stays at rest or continues to move at constant velocity unless a resultant force acts on it.

Question 2

● Newton’s Second Law:

Answer 2

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

Question 3

● Newton’s Third Law:

Answer 3

Whenever body A exerts a force on body B, body B exerts an equal but oppositely directed force of the same kind on body A.

Question 4

● Momentum:

Answer 4

Momentum of a body is the product of its mass and velocity.

Question 5

● Impulse (of a force):

Answer 5

Product of the force and the duration for which the force acts.

Question 6

● Principle of conservation of momentum:

Answer 6

In the absence of an external resultant force acting on a system of interacting bodies the total momentum of the system remains constant.

Question 7

Whats the importance of a head-on collision of two bodies

Answer 7

In a head-on collision of two bodies, the velocity vectors of the two bodies are always parallel to the straight line connecting the centre of mass of each of the bodies.