Centre Of Mass

Introduction An object may be made to balance at a particular point. When it is balanced at this point, the object does not turn and all the weight on one side of the pivot is balanced by the weight on the other side. This point is called the centre of mass, or centre of gravity, … Read more

Newton’s Laws Of Motion

Introduction Newton’s laws of motion are three physical laws that describe the relationship between a body and the forces acting upon it, and its motion in response to those forces. In general, the first law defines the force qualitatively, the second law offers a quantitative measure of the force, and the third asserts that a … Read more

Projectile Motion

Introduction Consider a car that is moving in a straight line. The motion of the car is one-dimensional. Now, consider a ball kicked by a football player. The motion of the ball is two-dimensional, as illustrated in Figure 1. In this article, the concept of two-dimensional motion and the equations that govern the two-dimensional motion … Read more

Scalars & Vectors

Introduction Consider a car that is travelling from city A to city B. The distance travelled by the car can be calculated by multiplying the average speed of the car and the time taken. However, we cannot find out how far the car is from its starting point unless we are told the direction of … Read more

Conditions For Equilibrium

Introduction An object is said to be in equilibrium if the resultant force acting on the object is zero or the sum of the moments acting on the object is zero. This article discusses the methods to find out force equilibrium. A. Resolving Vectors In this method, all the vectors acting on an object are … Read more

Resolving Vectors

Introduction A quantity with magnitude and direction is defined as a vector quantity. The weight of an object, velocity, and acceleration of a vehicle and the force acting on a bridge are some examples of vector quantity. All vector quantities can be split, or resolved, into two components: Horizontal components and vertical components. The combined … Read more

Longitudinal & Transverse Waves

Introduction Wave motion is a means of moving energy from place to place. For example: the electromagnetic waves from the sun carry the energy to the Earth for the survival of living things. The energy from sound reaches our eardrums to vibrate. Waves that move energy from place to place without the transfer of matter … Read more


Introduction Refraction is the change of direction of wave that occurs when its speed changes. Refraction is a phenomenon that is exhibited by wave when it travels from one medium to another, for example, when light travels from air to glass or vice versa. Refraction can be also be seen when water waves move from … Read more


Introduction If two or more waves collide, they are said to interfere. Interference is a property of waves. In this article, how interference occurs in different types of waves is explained. Figure 1: Interference of Waves A. Interference If two or more waves overlap, the resultant displacement is the sum of the individual displacements. Displacement … Read more

Progressive Waves

Introduction Waves, which move from place to place without the transfer of matter, are called progressive waves. In this article, important properties of progressive waves are explained. A. Displacement The displacement of a particle on a wave is its distance in a specified direction from its position. A transverse wave is represented by plotting displacement … Read more