**PART II **: **PHYSICS (15 Marks)**

**Syllabus**

Module I - 4 Marks

**Units and Measurements:**

System of Units – CGS and S.I System, Multiples & sub multiples of unit, Parallax method – for measurement of large distances, Significant figures, Accuracy and Precision, Errors in measurement and Calculation.

Kinematics – Motion in a straight line and plane.

Kinematics – Motion in a straight line and plane.

Graphical representation of motions – Position time graph and velocity time graph, Equation of motion, Displacement and distance, Velocity and acceleration, Vector addition – Triangular law and Parallelogram law, Uniform circular motion – Centripetal force and acceleration.

**✅ Dynamics**

Laws of motion and Work, Energy & Power.

Newton’s laws of motion, Impulse and its application, Law of conservation of momentum – Recoil of gun, Friction – Laws of static and kinetic friction, angle of repose, Methods of reducing friction.

Newton’s laws of motion, Impulse and its application, Law of conservation of momentum – Recoil of gun, Friction – Laws of static and kinetic friction, angle of repose, Methods of reducing friction.

Different types of work, Kinetic and Potential energy, Power, Collision -Elastic and Inelastic collision.

System of Particles and Rotational motion & Gravitation

Law of conservation of angular momentum and its application, Torque and Angular momentum, Moment of Inertia of regular bodies – Ring, disc, sphere and Cylinder, Theorem on Moment of Inertia – Parallel axes and Perpendicular axes, Kinetic energy of rolling bodies

System of Particles and Rotational motion & Gravitation

Law of conservation of angular momentum and its application, Torque and Angular momentum, Moment of Inertia of regular bodies – Ring, disc, sphere and Cylinder, Theorem on Moment of Inertia – Parallel axes and Perpendicular axes, Kinetic energy of rolling bodies

Acceleration due to gravity (g) and its variation with depth and height, Orbital velocity and time period of satellite, Escape velocity, Kepler’s third law.

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**Dynamics-**

**Laws of motion Inertia: **

**INERTIA**The inability of a body to change by itself it's state of rest or uniform motion along a straight line is called inertia.

**Examples of inertia: **

1. When a fast-moving bus is suddenly stopped, a standing passenger tends to fall in the forward direction.

**Explanation**

The passenger has the same velocity as that of the bus. When the bus stops suddenly the lower part of his body is brought to rest suddenly because of the friction between his feet and floor of the bus. But the upper part continues to move because of its inertia

2. When a bus suddenly takes off, a standing passenger tends to fall in the backward direction. This is because the lower part of the body gets a speed when the bus picks up speed and upper part continues to be at rest because of its inertia.

3. Consider a person sitting inside a stationary train and tossing a coin. The coin falls into his own hand. If he repeats the experiment when the train is moving with uniform speed, then also the coin falls into his own hand

**Newton's Laws: **

Newton built on Galileo's ideas and laid the foundation of mechanics in terms of three laws.

**1.Newtons first law**

**2. Newtons second law**

**3.Newtons third law**

**Newton's First Law Of Motion**

Everybody continues in its state of rest or of uniform motion along a straight line unless it is compelled by an external unbalanced force to change that state:

**Note**:

Newton's first law of motion brings the idea of inertia.

Inertia of a body is measured by the mass of the body. Heavier the body, greater is the force required to change its state and hence greater is its inertia

Inertia of a body is measured by the mass of the body. Heavier the body, greater is the force required to change its state and hence greater is its inertia

**Newton's Second Law Of Motion **

**Linear Momentum (p):**

Momentum of a body is defined as the product of its mass m and velocity v

**Explanation**

Momentum of a body can be produced or destroyed by the application of force on it.

Therefore, momentum of a body is measured by the force required to stop the body in unit time.

Force required to stop a moving body

depends upon

depends upon

- mass of the body
- velocity of the body

**1. Mass of the body:**When a ball and a big stone are allowed to fall from the same height, we find that a greater force is required to stop the big piece of stone than the ball. Thus larger the mass of a body, greater is its linear momentum.

**2. Velocity of the body:**

A bullet thrown with the hand can be stopped easily than the same bullet fired from the gun.

Therefore, langerthe velocity of a body, greater is its linear momentum.

**Note**:

Momentum is a vector quantity.

Its unit is Kgms-1

**Newton's Second Law of motion:**

The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts.

Mathematically this can be written as

F=ma

Unit of force: Unit of force is newton.

1N = 1Kgms-2

Force in terms of the components:

We know force is a vector,

Hence we can write as F=dp/dt

**Impulsive force:**

The forces which art on bodies for short time are called impulsive forres

Example:

- In hitting a ball with a bat
- In firing a gun

**Impulse: **

An impulse force does not remain constant, but changes from zero to maximum. This impulsive force is not easy to measure, because it changes with time. In such a case, we measure the total effect of the force called impulse.

The impulse of a force is the product of the average force and the time for which it acts.

The impulse of a force is the product of the average force and the time for which it acts.

IMPULSE=F*T

Relation between impulse and momentum:

we know from Newtons second law Newtons

we know from Newtons second law Newtons

**Third Law Of Motion Statement:**

To every action, there is always an equal and opposite reaction.

Explanation: When a book is placed on the table, the weight of the book acts on the table downwards. The table exerts an equal force on the book in the upward direction.

If the force applied by the book on the table is action, the force applied by the table on the book is reaction If action and reaction are equal and opposite, why they do not cancel?

**Answer**:

Though action and reaction are equal and opposite, they do not cancel each other because action is on one body and reaction is on another body.

Consider a pair of bodies A and B.

According to the third law

**FAB = - FBA**

(force on A by B) = - (force on B by A)