ICSE Class 9 Physics - Laws of Motion Flashcards

A set of vocabulary-based flashcards covering the key concepts, formulas, and units from ICSE Class 9 Physics Chapter 3: Laws of Motion.

Force

An influence that can change the state of rest or motion of an object.

Formula for Force ($F$)

$$F = ma$$

Formula for Momentum ($p$)

$$p = mv$$

Universal Law of Gravitation Formula

$$F = \frac{GMm}{r^2}$$

Weight Formula ($W$)

$$W = mg$$

Acceleration due to gravity ($g$)

$9.8\,m/s^2$ or approximately $10\,m/s^2$

Gravitational Constant ($G$)

$$6.67 \times 10^{-11}\,N\,m^2\,kg^{-2}$$

Mass of Earth

$$6 \times 10^{24}\,kg$$

Radius of Earth

$$6.4 \times 10^6\,m$$

Contact Force

A force that acts when objects are physically touching, such as friction or tension in a rope.

Non-contact Force

A force that acts without physical contact, such as gravity or magnetic force.

Newton's First Law

The law which states that an object's state of rest or motion will not change unless an external force acts on it; also known as the Law of Inertia.

Inertia

The inherent property of an object to resist any change in its state of rest or motion.

Inertia of Rest

The tendency of an object to remain at rest unless acted upon by an external force.

Inertia of Motion

The tendency of an object to continue in its state of uniform motion unless an external force is applied.

Inertia of Direction

The tendency of an object to resist a change in its direction of motion.

Mass

The measure of the amount of matter in an object; it is a scalar quantity.

Momentum

The quantity of motion in a moving body, calculated as the product of mass and velocity ($p = mv$).

Newton (N)

The SI unit of force; defined as the force that gives a mass of $1\,kg$ an acceleration of $1\,m/s^2$.

Dyne (dyn)

The CGS unit of force.

Relation between Newton and Dyne

$$1\,N = 10^5\,dyne$$

Kilogram-force (kgf)

A gravitational unit of force representing the force with which Earth attracts a mass of $1\,kg$ ($1\,kgf = 9.8\,N$).

Newton's Second Law

The law stating that the rate of change of momentum is proportional to the applied force ($F = ma$).

Newton's Third Law

The law stating that for every action, there is an equal and opposite reaction.

Impulse

The product of force and time, equal to the change in momentum ($Impulse = \Delta p = F \times t$).

Free Fall

The state of an object falling towards Earth solely under the influence of gravity.