LAWS IF MOTION 🍏🔬🩺🧑‍⚕️

9th class wala lalua concept smjhana force ka

Force is a push or pull

May change speed direction or both shape or size stop a moving oject or move aan from rest

PQ vector

SI unit kg m per second square

CGS unit g cm per second square or dyne

F=MLT²

Explain the concept of balanced and unbalanced forces

When forces are being applied on sn object such that they cancel each other gives us net force zero hence balanced force

(Balanced force don't give any accln to the body but it can change the shape and size of object )

When forces applied on a body give net resultant non zero then there will be accln on the object in the direction of net force hence unbalanced force

( Can do everything a force can do )

What do you understand by inertia ?

What is the quantitative measurement or numeriapcal measurement of a body inertia

Inertia is that property if body that opposes any change intpits state of rest of state of motion means the tendency of body to remain at whatever state it is whether it is in motion or at rest

Mass of the body

Inertia is directly proportional to the mass of the body

Here we go to define first law of of motion through different parameters

1 what it explains about

2 second name for it

If a body is at rest it will remain in rest and if in motion remain in motion (constant velocity ) until and unless an external unbalanced force

It explains about inertia

Law of inertia

To know about second law of motion which physical quantity should be understood

MOMENTUM

Explain the second law of motion

Listen second law of motion is not f =ma

Rate of change of momentum with respect to time of any system is directly proportional to the applied external force

Which formula are true according to second law

What is second law

Force = dp by dt

Force =v dm by dt

Force = ma

Force = m dv by dt

FORCE = dp by dt

MOMENTUM v/sc TIME graph

This graph slope gives Finst (Fext )

Key points 1 AREA NDER FORCE V/S TIME GRAPH

Solve it

Solve it

Solve it

Which law give qualitative and which law give quantitative description about force and how

First law gives quality as it explains about inertia

2nd law give qualitative cause it give the formula to calculate force

Speed thrills but kills

On this note whatever you have learnt about change in momentum (2nd lawa of motion)

Explain it in short

We know that external force is equal to the change in momentum with respect to time

Force is inversely proportional to time

So when a body is traveling with a very a high speed and get a sudden stop I mean it's velocity becomes 0 at an instant the force it experience is so large

But if the body slows down I mean if the velocity decrease gradually and become zero ultimately it won't experience a large force on it

Explain third law of motion in points

When one body exerts force on the other body the other body exerts force of equal magnitude but opposite dirn force on that body

( Every action has a equal and opposite reaction )

This action and reaction takes place simultaneously and can't be identified

And both the forces are of same nature

Examples

Rocket don't exert force on the air actually the fuel going through combustion reaction inside the rocket produces a large amount of gases and that gases are released outside with a large force from its thrust

A rocket moves forward by pushing exhaust gases backward

Action and reaction never cancel each other out each other

Why ???

Cause they act on two different bodies

Solve it

Solveit

Force → integrated → momentum → divide by mass → velocity→integrate → position

Solve it

NOT AGAINNN!!!!!! #UNIT CONVERSION#

Remember it

Solve it

Vectors

Basic maths

Differentiation and integration ,🥺🥺🥺🥺🥺🥺

IMPULSE

Vector PQ

In dirn of change in momentum

SI unit is kg m per second

MLT^-¹

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