Force, work, power and energy

• Muscular force – It involves the action of muscles.
  • Animals make use of muscular force to carry out their physical activities and other tasks.  
• Friction – It is an opposing force that acts between surfaces in contact moving with respect to each other. 
  • Frictional force always acts between two moving objects, which are in contact with one another.
  • Frictional force always acts opposite to the direction of motion.
  • Frictional force depends on the nature of the surface in contact.
• Tension Force - This force appears in a string, attached to a rigid support, when an object is suspended by it.
• Mechanical Force - It involves the force generated by machines.
• Force exerted during collision -Two objects push each other with an equal but opposite forces if collision occurs between them. These forces are known as the force of action and force of reaction.
• Combined Forces - When two or more forces are acting on the same object.

• Non-contact force come into play even when the bodies are not in contact.
• Magnetic force – Force acting between two magnets or a magnet and a magnetic material (eg. iron, steel, nickel, cobalt etc.). It can be attractive and repulsive.
• Electrostatic force – Force due to electric charges. It can be attractive and repulsive.
• Gravitational force – It is a kind of attractive force that comes into…