Key Concepts in Physics

Key Concepts in Physics

Fundamental Forces

1. Gravity:

   • Attracts two masses.
   • Weakest of the four forces.

2. Electromagnetism:

   • Acts between charged particles.
   • Responsible for electricity and magnetism.

3. Weak Nuclear Force:

   • Responsible for radioactive decay.
   • Plays a key role in nuclear reactions.

4. Strong Nuclear Force:

   • Holds protons and neutrons together in the nucleus.
   • Strongest force but operates at very short ranges.

Laws of Motion (Newton's Laws)

1. First Law (Inertia):

   • An object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net external force.

2. Second Law (F=ma):

   • The force acting on an object is equal to the mass of the object multiplied by its acceleration.

3. Third Law (Action-Reaction):

   • For every action, there is an equal and opposite reaction.

Energy

• Kinetic Energy:

  • Energy of motion, calculated as ( KE = \frac{1}{2}mv^2 ).

• Potential Energy:

  • Stored energy based on position, commonly gravitational ( PE = mgh ).

• Conservation of Energy:

  • Energy cannot be created or destroyed, only transformed.

Waves and Oscillations

• Wave Properties:

  • Wavelength, frequency, amplitude, and speed.

• Types of Waves:

  • Mechanical (requires medium) vs. Electromagnetic (can travel through vacuum).

Thermodynamics

1. First Law:

   • Energy cannot be created or destroyed (conservation of energy).

2. Second Law:

   • Entropy of an isolated system always increases.

3. Third Law:

   • As temperature approaches absolute zero, the entropy of a perfect crystal approaches zero.

Electromagnetism

• Coulomb’s Law:

  • Describes electric force between charges; proportional to product of charges and inversely proportional to the square of the distance.

• Faraday’s Law of Induction:

  • A change in magnetic field can induce an electric current in a conductor.

Relativity

• Special Relativity:

  • Time dilation and length contraction occur at high speeds; speed of light is constant in a vacuum.

• General Relativity:

  • Gravity is the curvature of spacetime caused by mass.

Quantum Mechanics

• Wave-Particle Duality:

  • Particles exhibit both wave-like and particle-like properties.

• Uncertainty Principle:

  • It is impossible to know both the position and momentum of a particle precisely at the same time.

Essential Formulas

• Kinematics: ( d = vt + \frac{1}{2}at^2 )
• Momentum: ( p = mv )
• Work: ( W = Fd \cos(\theta) )
• Power: ( P = \frac{W}{t} )
• Ohm’s Law: ( V = IR )

Important Units

• Length: Meter (m)
• Mass: Kilogram (kg)
• Time: Second (s)
• Force: Newton (N)
• Energy: Joule (J)
• Power: Watt (W)

Applications of Physics

• Engineering
• Medicine (radiology, MRI)
• Astronomy
• Environmental Science (renewable energy sources)

Fundamental Forces

• Gravity: Attracts two masses. Weakest of the four forces.
• Electromagnetism: Acts between charged particles. Responsible for electricity and magnetism.
• Weak Nuclear Force: Responsible for radioactive decay. Plays a key role in nuclear reactions.
• Strong Nuclear Force: Holds protons and neutrons together in the nucleus. Strongest force but operates at very short ranges.

Laws of Motion (Newton's Laws)

• First Law (Inertia): An object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net external force.
• Second Law (F=ma): The force acting on an object is equal to the mass of the object multiplied by its acceleration.
• Third Law (Action-Reaction): For every action, there is an equal and opposite reaction.

Energy

• Kinetic Energy: Energy of motion, calculated as ( KE = \frac{1}{2}mv^2 ).
• Potential Energy: Stored energy based on position, commonly gravitational ( PE = mgh ).
• Conservation of Energy: Energy cannot be created or destroyed, only transformed.

Waves and Oscillations

• Wave Properties: Wavelength, frequency, amplitude, and speed.
• Types of Waves: Mechanical (requires medium) vs. Electromagnetic (can travel through vacuum).

Thermodynamics

• First Law: Energy cannot be created or destroyed (conservation of energy).
• Second Law: Entropy of an isolated system always increases.
• Third Law: As temperature approaches absolute zero, the entropy of a perfect crystal approaches zero.

Electromagnetism

• Coulomb’s Law: Describes electric force between charges; proportional to the product of charges and inversely proportional to the square of the distance.
• Faraday’s Law of Induction: A change in magnetic field can induce an electric current in a conductor.

Relativity

• Special Relativity: Time dilation and length contraction occur at high speeds; speed of light is constant in a vacuum.
• General Relativity: Gravity is the curvature of spacetime caused by mass.

Quantum Mechanics

• Wave-Particle Duality: Particles exhibit both wave-like and particle-like properties.
• Uncertainty Principle: It is impossible to know both the position and momentum of a particle precisely at the same time.

Essential Formulas

• Kinematics: ( d = vt + \frac{1}{2}at^2 )
• Momentum: ( p = mv )
• Work: ( W = Fd \cos(\theta) )
• Power: ( P = \frac{W}{t} )
• Ohm’s Law: ( V = IR )

Important Units

• Length: Meter (m)
• Mass: Kilogram (kg)
• Time: Second (s)
• Force: Newton (N)
• Energy: Joule (J)
• Power: Watt (W)

Applications of Physics

• Engineering
• Medicine (radiology, MRI)
• Astronomy
• Environmental Science (renewable energy sources)

Explore the foundational concepts of physics including fundamental forces like gravity and electromagnetism, as well as Newton's Laws of Motion. Test your understanding of energy types and their applications in real-world scenarios. Perfect for students looking to solidify their knowledge in physics fundamentals.