NEWTON'S 2ND LAW OF MOTION
STATEMENT:
When an unbalanced force acts upon a body, it is accelerated in the direction of
force.
The magnitude of acceleration is directly proportional to the applied
force and is inversely proportional to the mass of body.
MATHEMATICALLY
Combining (i) and (ii)
....
a = k (F)(1/m)
here
constant k=1
a= (1)(F)(1/m)
Or
SECOND STATEMENT
With the help of above equation 2nd law of motion can be expressed as:
THE NET FORCE ACTING ON A BODY IS EQUAL TO THE PRODUCT
OF THE MASS OF BODY AND THE ACCELERATION PRODUCED IN IT.
NEWTON'S 3RD LAW OF MOTION
STATEMENT:
"To every action there is a reaction equal in magnitude but opposite in
direction"
OR
"When a body exerts a force on another body, the second body also exerts
a force on the first body of same magnitude but in the opposite direction"
FACTION = -FREACTION
Force exerted by one body is called ACTION and the force exerted by the
second body is called REACTION.
EXAMPLES:
(1) Motion of rocket: fuel burns rapidly, exerts force in downward direction
and rocket moves upward
as a reaction.
(2) Book lying on a table: weight of the book on the surface is action and
the force exerted by the surface (R) is the reaction.
R = -W
(3) Walking on a street
(4) Motion of helicopter