2. NEWTON’S LAWS OF MOTION
STANDARED : IX
PREPARED BY :
ANU RESHMI.S
B.ED PHYSICAL SCIENCE
F.M.T.C
PALLIMUKKU
KOLLAM
OBJECTIVES:
1.To learn more about newton’s laws of motion
2.To find more examples of Newton’s laws of
motion
3.To enable the students for self learning
3.
4. Isaac Newton (1643–1727), the physicist who formulated the laws
Newton's laws are applied to objects which are idealised as single point masses, in the sense
that the size and shape of the object's body are neglected to focus on its motion more easily.
This can be done when the object is small compared to the distances involved in its
analysis, or the deformation and rotation of the body are of no importance. In this way,
evena planet can be idealised as a particle for analysis of its orbital motion around a star.
5. I. Every object in a state of uniform motion tends to
remain in that state of motion unless an external force
is applied to it.
".
Explanation of Newton's first law .
The first law states that if the net forceis zero, then the velocity of the object is constantAn object
that is at rest will stay at rest unless an external force acts upon it.
6. II. The relationship between an object's mass m, its
acceleration a, and the applied force F is F = ma.
Acceleration and force are vectors (as indicated by
their symbols being displayed in slant bold font); in
this law the direction of the force vector is the same
as the direction of the acceleration vector.
This is the most powerful of Newton's three Laws, because it allows quantitative
calculations of dynamics: how do velocities change when forces are applied.
Newton's third law
III. For every action there is an equal and opposite
reaction.
This law is exemplified by what happens if we step off a boat onto the bank of a lake: as we
move in the direction of the shore, the boat tends to move in the opposite direction (leaving
us facedown in the water, if we aren't careful!
An illustration of Newton's third law in which two skaters push against each other. The first
skater on the left exerts a normal force N12 on the second skater directed towards the right, and
the second skater exerts a normal force N21 on the first skater directed towards the left.The
7. magnitudes of both forces are equal, but they have opposite directions, as dictated by Newton's
third law.
