SimplyTuition OL Combined Physics Volume I. Definitions & Formulas

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© 2025 Simply Tuition. All Rights Reserved. 2 Physical quantity is a quantity that can be measured. It consists of a magnitude and a unit. Base quantity is a physical quantity that is defined and measured independently of other quantities. Derived quantity is a physical quantity that is defined in terms of the base quantities. Parallax error is the error that occurs due to incorrect positioning of the eyes while taking a reading on the measuring scale. Zero error is a type of systematic error that occurs in measuring instruments when they do not start from exactly zero. Random error refers to unpredictable variations in measurements caused by uncontrollable factors, leading to scattered data around the true value. Scalar quantities are physical quantities that have only magnitude. Vector quantities are physical quantities that have both magnitude and direction. Distance, 𝒅 is the total length covered by a moving object regardless of its direction of motion. Displacement, 𝒔 is the distance measured in a straight line from a fixed reference point. 𝑠 = 𝑢𝑡 + 1 2 𝑎𝑡2 Speed, |𝒗| is the distance moved per unit time. (𝑠𝑝𝑒𝑒𝑑) |v| = |𝑢| + 𝑎𝑡 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑆𝑝𝑒𝑒𝑑 = 𝑇𝑜𝑡𝑎𝑙 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑇𝑜𝑡𝑎𝑙 𝑇𝑖𝑚𝑒 Velocity, 𝒗 is the rate of change of displacement. (𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦) 𝑣 = 𝑢 + 𝑎𝑡 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 = 𝑇𝑜𝑡𝑎𝑙 𝐷𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡 𝑇𝑜𝑡𝑎𝑙 𝑇𝑖𝑚𝑒 Acceleration, 𝒂 is the rate of change of velocity. 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝐴𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 = ∆𝑣 ∆𝑡 = 𝑣 − 𝑢 𝑡 Uniform acceleration is a constant rate of change of velocity. Force is a push or pull. Gravitational force, 𝑭𝑮 is the pull exerted by Earth’s gravity on any object. Electrostatic force, 𝑭𝑬 is the attractive or repulsive forces between electric charges. Magnetic force, 𝑭𝑴 is the attractive or repulsive forces between magnets. Friction, 𝒇 is the force that opposes or tends to oppose motion between surfaces in contact. Air resistance is the frictional force exerted by air that opposes the motion of moving objects. Normal force, 𝑵 is the push exerted by a surface on an object pressing on it. This push is always perpendicular to the surface. Tension, 𝑻 is the pull exerted by a stretched spring, string, or rope on an object attached to it.

© 2025 Simply Tuition. All Rights Reserved. 3 Mass, 𝒎 is a measure of the amount of matter in a body. Weight, 𝑾 is the gravitational force acting on an object that has mass. 𝑊 = 𝑚𝑔 Gravitational field is a region in which a mass experiences a force due to gravitational attraction. Gravitational field strength, 𝒈 is defined as the gravitational force per unit mass placed at that point. 𝑔 = 𝑊 𝑚 Newton’s first law of motion states that every object will continue in its state of rest or uniform motion in a straight line unless a resultant force acts on it. Newton’s second law of motion states that when a resultant force, ∑ 𝐹 acts on an object of a constant mass, the object will accelerate in the direction of the resultant force. ∑ 𝐹 = 𝑚𝑎 Newton’s third law of motion states that if a body A exerts a force, 𝐹𝐴𝐵 on body B, then body B will exert an equal and opposite force, 𝐹𝐵𝐴 on body A. Terminal velocity is the velocity at which a falling object experiences zero acceleration and travels at a constant speed. It occurs when the air resistance acting against the object equals its weight. Moment of a force, 𝑴 or torque, 𝜏 about a pivot, is the product of the force, 𝐹 and the perpendicular distance, 𝑑⊥ from the pivot to the line of action of the force. 𝑀 = 𝐹𝑑⊥ Principle of moments states that that when a body is in equilibrium, the sum of clockwise moments about a pivot is equal to the sum of anticlockwise moments about the same pivot. Taking moments about X, CW = ACW 𝐹1 ∗ 𝑑1,⊥ = 𝐹2 ∗ 𝑑2,⊥ Centre of gravity is an imaginary point where the entire weight of the object seems to act. Pressure, 𝑷 is the force acting per unit area. 𝑃 = 𝐹 𝐴 Density, 𝝆 is defined as mass per unit volume. 𝜌 = 𝑚 𝑉 Energy is defined as the ability to do work. Principle of conservation of energy states that energy cannot be created or destroyed. Energy can only be transferred from one store to another. The total energy of an isolated system is constant.

© 2025 Simply Tuition. All Rights Reserved. 4 𝐸𝑘 = 1 2 𝑚𝑣2 𝐸𝑝 = 𝑚𝑔ℎ Work done, 𝑾 by a constant force on an object is the product of the force and the displacement moved by the object in the direction of the force. 𝑊 = 𝐹𝑠 Power, 𝑷 is defined as the work done or energy transferred per unit time. 𝑃 = 𝑊 𝑡 Efficiency, 𝜼 is the ratio of useful output energy (or power) to the total input energy (or power). 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦, 𝜂 = 𝑜𝑢𝑡𝑝𝑢𝑡 𝑝𝑜𝑤𝑒𝑟 𝑖𝑛𝑝𝑢𝑡 𝑝𝑜𝑤𝑒𝑟 × 100% Kinetic particle model of matter is made up of tiny particles that are in continuous motion. Temperature rises with average kinetic energy of the particles in a body and vice versa. Thermal equilibrium describes a state in which two or more objects have the same temperature and there is no net transfer of energy between them. Conduction is a process of energy transfer where energy is transferred through the passing on of vibrational motion from one particle to another. Convection is a process of energy transfer by means of convection currents of a fluid (liquid or gas), due to a difference in density. Radiation is the process of energy transfer by electromagnetic waves. It does not require a medium. Wave is a disturbance that propagates through space, transferring energy with it but not matter. Transverse waves have a direction of vibration that is perpendicular to the direction of wave travel. Longitudinal waves have a direction of vibration that is parallel to the direction of wave travel. Amplitude, 𝒙𝟎 of a wave is its maximum displacement from its equilibrium position. Period, 𝑻 is the time taken by each point on the wave to complete one oscillation. 𝑇 = 1 𝑓 Frequency, 𝒇 is the number of oscillations each point completes per second. Wavelength, 𝝀 is the shortest distance between two successive crests or troughs. Wave speed, 𝒗 is the distance travelled by a wave per second. 𝑣 = 𝑓𝜆 𝑣 = 𝑓 𝑇 Wavefront is an imaginary line joining all adjacent points that are in phase.

© 2025 Simply Tuition. All Rights Reserved. 5 Soundwave is a longitudinal wave that propagates through a medium. The vibration of particles within the medium causes a series of compressions and rarefactions, resulting in the transmission of energy from one point to another. Ultrasound is sound with frequencies above the upper limit of the human audible range (≥ 20𝑘𝐻𝑧). Electromagnetic waves are transverse waves made up of oscillating electric and magnetic field which travel at 3.0 × 108 𝑚/𝑠 in a vacuum, without the need for a medium. First law of reflection states that the incident ray, reflected ray, and the normal at the point of incidence lie in the same plane. Second law of reflection states that the angle of incidence 𝜃𝑖. is equal to the angle of reflection 𝜃𝑟. Refraction is the bending of light as it passes from one optical medium to another. First law of refraction states that the incident ray, refracted ray, and the normal at the point of incidence all lie in the same plane. Second law of refraction states that for two given media, the ratio of the sine of angle of incidence to the sine of the angle of refraction is a constant, that is sin 𝑖 sin 𝑟 = 𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡. Refractive index, 𝒏 of a medium is defined as the ratio of the speed of light in a vacuum to the speed of light in that medium. 𝑛 = 𝑐 𝑣 𝑛 = sin 𝑖 sin 𝑟 Principle of reversibility of light rays states that regardless of how many times a light ray has been reflected or refracted, it will follow the same path when its direction is reversed. Principal axis is the line which passes through the centre of the lens and is perpendicular to the plane of the lens. Focal point / principal focal point, 𝑭 is the point on the principal axis where all the r