Starting with the definitions of momentum and kinetic energy, derive an equation for the kinetic energy of a particle expressed as a function of its momentum.

Short Answer

Expert verified

The equation for the kinetic energy of a particle expressed as a function of its momentum is, \(K.E. = \dfrac{1}{2}pv\)

Step by step solution

01

Explaining the equation for kinetic energy.

The equation for the kinetic energy of a particle having mass, m and having a velocity, vis given by,

\(K.E. = \dfrac{1}{2}m{v^2}\) …………………. (1)

02

Explaining the equation for momentum

The momentum of the same particle (as described above) having a mass mand having velocity v is,

\(p = mv\) ………………….2

On dividing both sides of the equation 2 by v, we get

\(\therefore \dfrac{p}{v} = \dfrac{{mv}}{v}\)

\(\therefore \dfrac{p}{v} = m\)…………………. 3

03

Derivation of the equation of kinetic energy of a particle expressed as a function of its momentum.

Substitute equation 3 in equation1, we get

\(K.E. = \dfrac{1}{2}\dfrac{p}{v}{v^2} = \dfrac{1}{2}pv\)

One vin the numerator cancels with the other v in the denominator.

Thus,

\(K.E. = \dfrac{1}{2}pv\)

The above equation is the equation for the kinetic energy of a particle expressed as a function of its momentum

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