App of Forces & Transfer of Energy

• Force is a push or a pull exerted when one thing interacts with another
• Examples of forces include lifting, bending, stretching, twisting, and squeezing
• Three important forces are frictional force, magnetic force, and gravitational force
• Frictional force occurs when two moving surfaces are in contact and can be reduced by using smooth surfaces, ball bearings, lubrication, and streamlining
• Magnetic force is exerted by a magnet on a magnetic material or another magnet
• Gravitational force, also known as gravity, causes all objects to be attracted to the Earth
• Force can be measured using force-meters, with the SI unit of force being the Newton (N)
• Weight of an object is due to the gravitational force acting on it, and weight = mass x gravitational field strength of Earth
• Mass is the amount of matter in an object, measured in kilograms, while weight is the force of Earth's gravitational pull on an object, measured in Newtons (N)
• Work is done when energy is transferred through the application of force to move an object in the direction of the force
• Work done = Force applied x Distance moved in the direction of force, with the SI unit of work being the joule (J)
• Energy cannot be created or destroyed. It can only be converted or transferred from one form of energy to another.
• The law of conservation of energy states that energy cannot be created or destroyed; it can only change forms.
• Potential energy is stored energy that has not yet been used to do work.
• Heat energy is the energy associated with temperature changes.
• Kinetic energy is the energy possessed by moving objects.
• KE= 1/2 x mass x speed squared
• When the mass of a moving object is doubled, its KE increases by 2 times
• When the velocity of a moving object is doubled, its KE increases by 4 times
• Velocity--> speed in particular direction
• The unit of KE is Joules (J)
• Gravitational Potential Energy (GPE)= 1/2 x mass x height x g
• When an object falls from rest, it gains GPE as well as kinetic energy.
• The unit of GPE is Joules (J)
• Elastic potential energy is stored when objects are stretched or compressed