Question #b123c

1 Answer
Apr 3, 2017

See below

Explanation:

If they have different formulae they are not the same:

  • Vector quantity momentum is mathbf p = m mathbf v. Momentum is always conserved in consequence of Newton's 2nd and 3rd Laws.

  • Scalar quantity Kinetic Energy is T = 1/2 m v^2. T is conserved, for example, in elastic collisions; but it is not always conserved.

In modern physics, they are often combined as:

T = p^2/(2m)

You are right in one sense though. For constant mass, they are both functions of velocity; but:

  • p propto v

  • T propto v^color(red)(2)

and

  • T propto p^2

A more interesting relationship might be, where x is displacement:

(dT)/dx = mv (dv)/dx = ma