Science Overview and Forces

Science Overview

• Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
• It involves observation, experimentation, and the formulation and testing of hypotheses.
• Key branches of science include physics, chemistry, biology, and Earth science.

Forces

• Forces are pushes or pulls that can cause changes in motion or shape of objects.
• There are various types of forces, including:
  • Gravity: The force of attraction between any two objects with mass.
  • Electromagnetic force: The force between charged particles, responsible for many phenomena like light and magnetism.
  • Strong nuclear force: The force that holds the particles in an atom's nucleus together.
  • Weak nuclear force: The force involved in certain types of radioactive decay.
  • Normal force: The force exerted by a surface on an object in contact with it.
  • Frictional force: The force that opposes motion between surfaces in contact.
  • Applied force: A force that is applied to an object by a person or another object.
• Forces are measured in Newtons (N).
• The effect of a force depends on its magnitude and direction.
• Forces can be balanced or unbalanced. Balanced forces result in no change in motion, while unbalanced forces cause changes in motion.

Energy

• Energy is the capacity to do work or cause change. It is a scalar quantity.
• There are many forms of energy, including:
  • Kinetic energy: The energy of motion. Depends on mass and velocity.
  • Potential energy: Stored energy due to position or configuration. e.g., gravitational potential energy, elastic potential energy.
  • Thermal energy: The internal energy of a substance due to the motion of its particles. Usually associated with heat.
  • Chemical energy: Stored energy in chemical bonds. Released in chemical reactions, e.g., combustion.
  • Electrical energy: Energy associated with electric charges.
  • Nuclear energy: Energy stored within the nucleus of an atom. Released in nuclear reactions.
  • Radiant energy: Energy that travels in the form of electromagnetic waves, like light and heat.
• Energy can be transformed from one form to another. For example, chemical energy in food is transformed into kinetic energy when we move.
• The law of conservation of energy states that energy cannot be created or destroyed; it can only be transformed from one form to another.
• Energy is measured in Joules (J).

Relationship between Force and Energy

• Force applied over a distance results in work.
• Work is a measure of energy transferred.
• The work-energy theorem states that the work done on an object is equal to the change in its kinetic energy.

Examples of Force and Energy

• A ball falling from a table demonstrates the relationship between gravitational potential energy and kinetic energy.
• A car accelerating is an example of a force (engine's push) changing its kinetic energy.
• Friction between surfaces transferring thermal energy.