Conservation of Energy Formula with Sample Problems

Conservation of Energy Formula :

Energy spent in one act=Energy gained in the related act

Conservation of Energy Formula is energy transform Ein subtraction  Energy of out Eout  is equal to the of any system occurs in the form of energy ΔEsys.Hence the conservation of Energy  formula can be written as

Ein  -Eout =ΔEsys

As we know the net amount of energy transfer into or out of any system occurs in the form of heat (Q), mass(m) and work (w).Hence we can rewrite the aforementioned equation as

Conservation of Energy formula is Energy into Ein and subtraction Energy out Eout  is equal to the of any system occurs in the form of heat Q(j) in joule and subtraction work of energy W(j) in joule. Hence the conservation of Energy formula can be written as

Ein  -Eout =Q(j)-W(j)

Upon dividing  all the terms into both sides of the equation by the mass of the system, the equation represents the law of conservation of energy on a unit mass basis as shown below

Q-W= Δu

Thus we can write the conservation of energy rate equation as

Q-W =du/dt

Sample Problems :

Problem 1:

Calculate the energy conservation of the system? The initial energy and the final energy of a system can be given by 6.450 × 10-3 and 3.460 × 10-3 respectively.

Solution :

We can use the following formula to compute the energy conservation of the system.

ΔEsys = Ein  -Eout

ΔE=(6.450 × 10-3) –(3.460 × 10-3 )

ΔE= 0.00299× 10-3

Problem 2:

Calculate the law of conservation of energy? In a particle of charge equal to that of electron and the charge is 1.67× 10-27 and mass of the particle is 1.30 × 10-27 kg.

Solution :

As per the law of conservation of energy formula, we have

Q-W= ΔEsys or

ΔEsys =Q-W

=(1.67 × 10-27 )-( 1.30 × 10-27 )

=0.37 × 1027

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