Question

compare the law conservation of momentum with the law of conservation of energy. Comment on meaning of variables/equations in each law including similarities between them.

Answer 1

Solution:

Law of conservation of momentum

It states that if no force is applied on a system then its momentum is conserved. let us take example of collsion, let two bodies of mass m1 and m2 are having initial velocities u1 and u2 after collision the velocities will be v1 and v2 Now as there is no external force applied, Hence

initial momentum = final momentum

=> m1 * u1 + m2 * u2 = m1*v1 + m2 * v2

Momentum is a vector quantity. So while applying law we use vector algebra

Law of conservation of Energy

According to this law , Energy can neither be created nor be destroyed but can be changed from one form to other. for example when an object is dropped from a height h then potential energy is converted to kinetic energy.

P.E = K.E (using law of conservation of energy)(not always true)

Energy is scalar quantity So it can be added or subtracted easily.