PHYSICS

SUMMER PROJECT

TOPIC -

NEWTON'S LAWS OF MOTION

WHO IS NEWTON

???

2

Isaac Newton (1643–1727), the physicist who formulated the laws of motion

3

3

SIR ISSAC NEWTON ( 25 December 1642 – 20 March 1726) was an English physicist and mathematician who is widely recognised as one of the most influential scientists of all time and as a key figure in the scientific revolution.

Newton's Principia formulated the laws of motion and universal gravitation, which dominated scientists' view of the physical universe for the next three centuries. 4

Philosophiæ Naturalis Principia Mathematica

("Mathematical Principles of Natural Philosophy"),a book

written by Issac Newton explains“the three laws of

motion”.

5

Newton's laws of motion

Newton's laws of motion are three physical laws that together laid the foundation for classical mechanics. They describe the relationship between a body and the forces acting upon it, and its motion in response to said forces.

The three laws of motion were first compiled by Isaac Newton in his Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), first published in 1687.Newton used them to explain and investigate the motion of many physical objects and systems. 6

THE THREE LAWSFirst Law- Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it.”

Second law- “Force is equal to the change in momentum(mV)per change in time. For a constant mass, force equals mass times acceleration”

F = ma

Third law- “For every action , there is an equal and opposite re-action”

7

A BRIEF DISCRIPTION OF THE NEWTON'S THREE LAWS OF

MOTION

8

THE F I R S T L A W

Newton's first law of motion states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia. The key point here is that if there is no net force acting on an object (if all the external forces cancel each other out) then the object will maintain a constant velocity. If that velocity is zero, then the object remains at rest. If an external force is applied, the velocity will change because of the force.

9

WHAT DOES 1ST LAW MEAN???

Basically, an object will “keep doing what it was doing” unless acted on by an unbalanced force.

If the object was sitting still, it will remain stationary. If it was moving at a constant velocity, it will keep moving.

It takes force to change the motion of an object.

10

In outer space, away from gravity and any sources of

friction, a rocket ship launched with a certain speed and

direction would keep going in that same direction and at that

same speed forever.

11

THE SECOND LAW

The second law explains how the velocity of an object changes when it is subjected to an external force. The law defines a force to be equal to change in momentum (mass times velocity) per change in time. Newton also developed the calculus of mathematics, and the "changes" expressed in the second law are most accurately defined in differential forms. (Calculus can also be used to determine the velocity and location variations experienced by an object subjected to an external force.) For an object with a constant mass m, the second law states that the force F is the product of an object's mass and its acceleration a:

F = m * a

12

WHAT DOES 'F=M*A' MEAN

l Force is directly proportional to mass and acceleration. Imagine a ball of a certain mass moving at a certain acceleration. This ball has a certain force.

l Now imagine we make the ball twice as big (double the mass) but keep the acceleration constant. F = ma says that this new ball has twice the force of the old ball.

l Now imagine the original ball moving at twice the original acceleration. F = ma says that the ball will again have twice the force of the ball at the original acceleration.

13

WHAT DOES F=ma SAY ???????

F = ma basically means that the force of an object comes from its mass and its acceleration.

Something very massive (high mass) that’s changing speed very slowly (low acceleration), like a glacier, can still have great force. Something very small (low mass)

that’s changing speed very quickly (high acceleration), like a bullet, can still have a great force. Something very small changing speed very slowly will have a very weak force.

14

THE THIRD LAW

For every action there is an equal and opposite reaction.

15

What does this mean?For every force acting on an object, there is an equal force acting in the opposite direction. Right now, gravity is pulling you down in your seat, but Newton’s Third Law says your seat is pushing up against you with equal force. This is why you are not moving. There is a balanced force acting on you– gravity pulling down, your seat pushing up.

16

What happens if you are standing on a skateboard or a slippery floor and push against a wall? You slide in the opposite direction (away from the wall), because you pushed on the wall but the wall pushed back on you with equal and opposite force.

17

THANKYOU

BY- VIKRAM BOGA