Question

What does it mean for a quantity to be conserved? Why are conserved physical quantities useful to physicists? Give an example which illustrates the difference between three kinds of energy and the transformation of energy from one kind to another. Your example may include some of the following kinetic, thermal, gravitational potential, and spring potential energy. In your example explain the difference between Energy, Work, and Power.

Answer 1

Quantity to be conserved means that quantity will not change through out the complete experiment/process.

for example momentum remains conserve in elastic/inelastic collisions and they are important to us because these quantities give us a set of equations to determine some unknowns . like in a elastic collision we know momentum and energy are conserve and that information is enough to determine outcomes of a elastic collisions.

1 . Kinetic energy - A form Energy due to the motion of body.

2. Potential energy - A form of energy due to the position of body.

3. Thermal energy - A form of energy due to temperature of body.

conversion - for example you drop a body from top of a building from rest and you realise that it acquires some velocity so that is conversion of potential energy due to height to Kinetic energy of body. In this example the work is done by force i.e. gravity , body has energy due to it's velocity and height. and power is rate of change of energy.

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