## Energy = mv^2

$\lambda=\frac{h}{p}$

EvaLi_3J
Posts: 53
Joined: Wed Oct 02, 2019 12:16 am

### Energy = mv^2

Hi!
I remember in class professor Lavelle talked about how we could derive E = mv^2 from E = mc^2. I'm just not entirely sure about this equation. Is E = mv^2 applicable in any cases? For example, if I want to calculate the total energy of a moving baseball, can I use this equation? Also, since Kinetic Energy = 1/2(mv^2), does it mean that kinetic energy is always half of the total energy (which I highly suspect)?

Amy Pham 1D
Posts: 103
Joined: Fri Aug 09, 2019 12:15 am

### Re: Energy = mv^2

In class, Dr. Lavelle generalized the E=mc^2 equation to E=mv^2 (no longer dealing with photons) so that we could derive the equation for De Broglie's wave equation, wavelength=h/p with variables that cancel out. As he stated, there exists a better derivation of the equation that does not deal with c at all, but it is more complicated and involved. So, for our purposes we generalized the equation to simply v, but this should not be used in other calculations.

Alex Hitti 3E
Posts: 51
Joined: Sat Aug 17, 2019 12:17 am

### Re: Energy = mv^2

Dr. Lavelle generalized the concept so I wouldn't use that equation since there are more complicated and accurate ways to achieve the derivation. He said to not worry about it too much since it won't be a main focal point in the midterms and finals.