Grade 11
  1. Mechanics  1.1. dynamics  1.1.1. Motion in one dimension  1.1.2. Motion in two and three dimensions  1.1.3. Displacement and Distance  1.1.4. Speed and Velocity  1.1.5. Acceleration and deceleration  1.1.6. Graphical analysis of motion  1.1.7. Equations of motion (advanced derivations)  1.1.8. Free fall and terminal velocity  1.1.9. Projectile motion  1.1.10. Relative velocity in one and two dimensions  1.1.11. Motion of a car on an inclined plane  1.2. Dynamics  1.2.1. Newton's laws of motion and their applications  1.2.2. Inertia and Newton's first law  1.2.3. Force and types of force  1.2.4. Static and kinetic friction  1.2.5. Circular motion and centripetal acceleration  1.2.6. Non-uniform circular motion  1.2.7. Banking of roads and curves  1.2.8. Momentum and Impulse  1.2.9. Conservation of momentum in one and two dimensions  1.2.10. Applications of Newton's Third Law  1.3. Work, Energy and Power  1.3.1. Work done by a constant and variable force  1.3.2. Work–energy theorem  1.3.3. Kinetic and potential energy  1.3.4. Gravitational and elastic potential energy  1.3.5. Conservation of mechanical energy  1.3.6. Power and instantaneous power  1.3.7. Efficiency of machines  1.3.8. Work done by conservative and non-conservative forces  1.4. Rotational motion  1.4.1. Torque and angular acceleration  1.4.2. Rotational equilibrium  1.4.3. Moment of inertia and its applications  1.4.4. Angular momentum and its conservation  1.4.5. Kinetic energy of rolling motion and rotation  1.4.6. Parallel and Perpendicular Axis Theorem  1.4.7. Dynamics of rotational motion
  2. Gravitational force  2.1. Universal gravitation  2.1.1. Newton's law of universal gravitation  2.1.2. Gravitational field and potential  2.1.3. Change in acceleration due to gravity  2.1.4. Kepler's laws of planetary motion  2.1.5. Orbital mechanics and satellites  2.1.6. Escape velocity and orbital velocity  2.1.7. Weightlessness and free fall  2.1.8. Gravitational potential energy and energy in orbits  2.1.9. Black holes and gravitational lensing
  3. Properties of matter  3.1. Fluid mechanics  3.1.1. Density and pressure in liquids  3.1.2. Pascal's theory and applications  3.1.3. Archimedes' Principle and Buoyancy  3.1.4. Bernoulli's equation and applications  3.1.5. Continuity equation and the Venturi effect  3.1.6. Surface tension and capillarity  3.1.7. Viscosity and Poiseuille's Law  3.1.8. Reynolds number and turbulence  3.2. Elasticity and deformation  3.2.1. Hooke's law and the stress-strain relation  3.2.2. Elastic modulus and applications  3.2.3. Deformation and yield strength of solids
  4. Thermal physics  4.1. Heat and temperature  4.1.1. Thermometric properties and temperature scale  4.1.2. Thermal expansion of solids, liquids and gases  4.1.3. Heat transfer system  4.1.4. Specific heat capacity and calorimetry  4.1.5. Latent heat and phase change  4.2. Kinetic theory of gases  4.2.1. Molecular model of gases  4.2.2. Kinetic explanation of temperature  4.2.3. Ideal Gas Equation and Deviations  4.2.4. Mean free path and Maxwell–Boltzmann distribution  4.3. Laws of Thermodynamics  4.3.1. Zeroth Law and Thermal Equilibrium  4.3.2. First Law and Internal Energy  4.3.3. The Second Law and Entropy  4.3.4. Carnot cycle and heat engines  4.3.5. Refrigerators and heat pumps
  5. Waves and oscillations  5.1. Simple Harmonic Motion  5.1.1. Equations of SHM  5.1.2. Energy in SHM  5.1.3. Damped and forced oscillations  5.1.4. Resonance and applications  5.1.5. Pendulum and spring-mass system  5.2. Wave motion  5.2.1. Types of mechanical waves  5.2.2. Wave motion and energy transport  5.2.3. Superposition Principle and Standing Waves  5.2.4. Reflection, Refraction and Diffraction  5.2.5. Doppler effect in sound and light  5.2.6. Pulsations and interference
  6. Electricity and Magnetism  6.1. Electrostatics  6.1.1. Electric charge and conservation  6.1.2. Coulomb's law and its applications  6.1.3. Electric field and electric flux  6.1.4. Electric potential and potential energy  6.1.5. Capacitance and Energy Stored in a Capacitor  6.2. Current Electricity  6.2.1. Ohm's law and electrical resistance  6.2.2. Resistivity and temperature dependence  6.2.3. Kirchhoff's Laws and Circuit Analysis  6.2.4. Electrical power and efficiency  6.2.5. Combination of resistors  6.3. Magnetism and Electromagnetism  6.3.1. Magnetic fields and their sources  6.3.2. Magnetic force on moving charges  6.3.3. Electromagnetic induction  6.3.4. Faraday's and Lenz's laws  6.3.5. Inductance and Transformer  6.3.6. Alternating current and its applications
  7. Optics  7.1. Reflection and Refraction  7.1.1. laws of reflection and refraction  7.1.2. Mirrors and lenses  7.1.3. Total internal reflection and optical fiber  7.2. Wave optics  7.2.1. Interference and Diffraction  7.2.2. Young's double-slit experiment  7.2.3. Polarization of light
  8. Modern Physics  8.1.1. Photoelectric effect and Einstein's theory  8.1.2. Wave–particle duality  8.1.3. Heisenberg's uncertainty principle  8.1.4. Compton Effect  8.2. Atomic and Nuclear Physics  8.2.1. Atomic model and energy levels  8.2.2. Radioactive decay and half-life  8.2.3. Nuclear Fission and Fusion
  9. Electronics and Communication  9.1. Semiconductors  9.1.1. pn junction and diode  9.1.2. Transistors and Logic Gates  9.1.3. Integrated Circuits and Applications  9.2. Communication Systems  9.2.1. Basics of Analog and Digital Communication  9.2.2. Wireless and Optical Communication  9.2.3. Modulation and Demodulation

Grade 11 → Mechanics → Dynamics ↓


Force and types of force


In the study of physics, particularly the branch of mechanics known as dynamics, the concept of force is fundamental. Force can be thought of as a push or pull on an object that can change its velocity, direction, or shape. Analyzing forces allows us to understand how objects move and interact with each other. Let's take a deeper look at the concept of force, the types of forces encountered in the physical world, and how they are represented and measured.

Understanding the force

Force is any interaction that changes the motion of an object without opposition. Force can change the velocity of an object with mass, i.e., accelerate it. Similarly, force can also cause an object to deform or change its shape. The simplest way to understand force is to think of it as a push or pull. The SI unit of force is the newton (N). One newton is the amount of force needed to give a mass of 1 kilogram an acceleration of 1 m/s².

The concept of force can be described by Newton's laws of motion. The first law, also called the law of inertia, states that an object will remain at rest or in uniform motion unless it is affected by a force. The second law provides a quantitative description of the effects of force and is expressed as:

F = m × a

Where:

  • F is the force applied to the object
  • m is the mass of the object
  • a is the acceleration generated

Types of forces

Forces can be broadly classified into two types: contact forces and non-contact forces. Each type has several specific forces that come into play in different physical situations.

Contact force

Contact forces require physical contact between two interacting objects. Some common types of contact forces are:

Friction force

Friction is the force which opposes the relative motion of two surfaces in contact or the tendency to such motion. It acts parallel to the surface and opposite to the direction of motion or intended motion.

box

Example: Pushing a box across the floor. Friction between the box and the floor resists motion.

Tension force

Tension is the force transmitted through a string, rope, cable or wire when it is pulled by forces acting from opposite ends. Tension is a pulling force and always acts along the length of the wire or cable.

Rope

Example: A game of tug of war in which each team pulls the rope, creating tension in it.

Normal force

Normal force is a supporting force applied to an object that is in contact with another stationary object. It acts perpendicular to the surface of the object.

object

Example: A book rests on a table. The table exerts a normal force upward on the book which balances its weight.

Applied force

Applied force is the force applied to an object by someone or another object.

Example: To open a door you have to apply force with your hand.

Spring force

Spring force is the force exerted by a compressed or stretched spring on any object attached to it. It is described by Hooke's law:

F = -k × x

Where:

  • F is the force exerted by the spring
  • k is the spring constant, which is a measure of the stiffness of the spring
  • x is the displacement of the spring from its equilibrium position

Example: Compressing a toy spring launcher before release.

Non-contact forces

Non-contact forces act at a distance without direct physical contact. These forces arise from the fields created by objects. The most common non-contact forces include:

Gravitational force

Gravity is the force of attraction between two bodies. It is the weakest of the four fundamental forces, but it is dominant over long distances and is responsible for the motion of celestial bodies. The gravitational force acting on an object on the surface of the Earth is said to be equal to the weight of the object and is expressed as:

F = m × g

Where:

  • F is the gravitational force
  • m is the mass of the object
  • g is the acceleration due to gravity, about 9.8 m/s²

Electromagnetic force

Electromagnetic forces arise from electric charges. This force includes both electric forces, which occur between stationary charges, and magnetic forces, which arise from moving charges or currents. Maxwell's equations describe these forces and how they interact.

Example: Repulsion between two like charges or attraction between opposite charges.

Nuclear forces

Nuclear forces include the strong and weak forces that act on the scale of the atomic nucleus. The strong nuclear force holds the protons and neutrons within the nucleus of an atom and is the strongest force known. The weak force is responsible for radioactive decay and neutrino interactions, and acts at even smaller distances.

Magnetic force

Magnetic force is related to electromagnetic forces, and acts on moving charges. It can be represented using magnetic field lines and affects materials differently depending on their properties.

Example: The force between the poles of a magnet or compass needle that are aligned with the Earth's magnetic field.

Conclusion

Understanding the different types of forces in mechanics and how they act on objects is very important. Forces are responsible for the motion and interactions of all physical objects, from the smallest particles to the largest celestial bodies. By studying forces, we gain important information about the workings of the natural world and the fundamental principles that govern everything in the universe.


Grade 11 → 1.2.3


U
username
0%
completed in Grade 11

← Prev (1.2.2)
Inertia and Newton's first law
Next (1.2.4) →
Static and kinetic friction

Comments 



Force and types of force

https://www.physicsflow.com/g11/1.2.3?pfal=en