Matric (SSC) Physics Syllabus

What is a random error and how can it be reduced?

An error that varies unpredictably in size and direction due to changing conditions or carelessness. It is reduced by taking several readings and using their mean (average).

Define rest and motion.

A body is at rest if it does not change its position with respect to its surroundings; a body is in motion if it changes its position with respect to its surroundings, both over time.

Why are rest and motion called relative states?

Because whether a body is at rest or in motion depends on the observer's reference (frame); a body at rest for one observer may be in motion for another.

What is translatory motion? Name its types.

Motion in which a body moves as a whole and every part moves the same distance in the same time. Types: linear (straight line), circular (circular path) and random (irregular, disordered path).

What is rotatory motion? Give an example.

The motion of a body turning about a fixed internal axis, with all particles moving in circles. Example: the spinning of a wheel or a top.

What is vibratory (oscillatory) motion? Give an example.

The to-and-fro motion of a body about a fixed mean position. Example: the motion of a pendulum or a swing.

How does circular motion differ from rotatory motion?

In circular motion a body moves along a circular path about an axis outside the body; in rotatory motion the body spins about an axis passing through itself.

What is a scalar quantity? Give two examples.

A quantity completely described by magnitude (number with unit) only. Examples: mass, time, distance, speed, energy.

What is a vector quantity? Give two examples.

A quantity that needs both magnitude and direction to be fully described. Examples: displacement, velocity, acceleration, force, weight.

How is a vector represented graphically and symbolically?

Graphically by an arrow whose length shows magnitude and whose head shows direction. Symbolically by a bold letter or a letter with an arrow over it, e.g. F or F⃗.

What is the difference between distance and displacement?

Distance is the total length of the path travelled (scalar); displacement is the shortest straight-line distance from the start to the end point in a specific direction (vector).

Define speed and state its SI unit and formula.

Speed is the distance covered per unit time (scalar). SI unit: metre per second (m/s). Formula: speed = distance ÷ time (v = S/t).

Define velocity and state its SI unit.

Velocity is the displacement per unit time, or rate of change of displacement (a vector). SI unit: metre per second (m/s).

What is the difference between uniform speed and variable speed?

Uniform speed: equal distances are covered in equal intervals of time. Variable speed: unequal distances are covered in equal intervals of time.

What is uniform velocity?

When a body covers equal displacements in equal intervals of time, i.e. moves with constant speed in a fixed direction (no change in speed or direction).

How do you convert a speed from km/h to m/s?

Multiply the value in km/h by 1000/3600, i.e. by 5/18. For example, 72 km/h = 72 × 5/18 = 20 m/s.

Define acceleration, give its SI unit and formula.

Acceleration is the rate of change of velocity (a vector). SI unit: metre per second squared (m/s²). Formula: a = (vf − vi) ÷ t.

What is the difference between positive acceleration and negative acceleration (deceleration)?

Positive acceleration: velocity increases with time (acceleration is in the direction of motion). Negative acceleration (deceleration/retardation): velocity decreases with time (acceleration opposes motion).

On a distance–time graph, what does the slope (gradient) represent?

The slope of a distance–time graph represents the speed of the body. A steeper slope means a greater speed; a horizontal line means the body is at rest.

On a velocity–time graph, what do the slope and the area under the line represent?

The slope represents acceleration, and the area under the line (between it and the time axis) represents the distance travelled.

On a velocity–time graph, what does a horizontal straight line indicate?

It indicates zero acceleration, i.e. the body is moving with uniform (constant) velocity.

State the first equation of motion.

vf = vi + a t (final velocity = initial velocity + acceleration × time).

State the second equation of motion.

S = vi t + ½ a t² (distance = initial velocity × time + half × acceleration × time squared).

State the third equation of motion.

2aS = vf² − vi² (twice acceleration × distance = final velocity squared − initial velocity squared).

For a body falling freely under gravity, how are the equations of motion modified?

Replace acceleration a with g (≈ 9.8 m/s², taken positive downward) and distance S with height h, e.g. vf = vi + g t and h = vi t + ½ g t².

Define force and state its SI unit.

Force is an agency (push or pull) that changes or tends to change the state of rest or uniform motion of a body. SI unit: newton (N).

Define inertia and state the factor on which it depends.

Inertia is the property of a body by which it resists any change in its state of rest or of uniform motion. It depends on (is directly proportional to) the mass of the body.

Define momentum, give its formula and SI unit.

Momentum is the quantity of motion of a body, equal to the product of its mass and velocity (a vector). Formula: p = m v. SI unit: kilogram metre per second (kg·m/s).

State Newton's first law of motion and the name given to it.

A body at rest stays at rest and a body in uniform motion continues in a straight line at constant speed unless acted on by a net external force. It is also called the law of inertia.

State Newton's second law of motion and give its mathematical form.

The acceleration of a body is directly proportional to the net force on it and in the same direction, and inversely proportional to its mass. Mathematically F = m a (one newton = 1 kg·m/s²).

State Newton's third law of motion and give an example.

For every action there is an equal and opposite reaction. Example: a swimmer pushes water backward (action) and the water pushes the swimmer forward (reaction).

Define friction and state its direction.

Friction is the force that opposes the relative motion (or tendency of motion) between two surfaces in contact. It always acts parallel to the surfaces and opposite to the direction of motion.

What is the difference between static friction and kinetic (dynamic) friction?

Static friction acts on a stationary body and prevents it from starting to move (up to a maximum, limiting friction). Kinetic friction acts on a body already in motion and is generally smaller than the limiting static friction.

State two advantages and two disadvantages of friction.

Advantages: enables walking, gripping and braking of vehicles; lets nails/screws hold. Disadvantages: wears out machine parts and tyres, and wastes energy/produces unwanted heat by opposing motion.