- #1
gulsen
- 217
- 0
1. Why do we have to assume mass doesn't change? And always use [tex]m_0[/tex]?
2. OK, let's assume we always use [tex]m_0[/tex]. Then why is momentum is defined as [tex]\frac{mv}{\sqrt{1-\frac{v^2}{c^2}}}[/tex]. If measuring in object's frame of reference, shouldn't we use his distance and time, where they are [tex]\frac{x_0}{\gamma(v)}[/tex] and [tex]t_0 \gamma(v)[/tex], and v would be [tex]\frac{x_0}{t_0 \gamma(v)^2}[/tex]. It seems that we're using [tex]x_0[/tex] either [tex]t_0[/tex] and not both, nor none. Isn't this inconsistent?
2. OK, let's assume we always use [tex]m_0[/tex]. Then why is momentum is defined as [tex]\frac{mv}{\sqrt{1-\frac{v^2}{c^2}}}[/tex]. If measuring in object's frame of reference, shouldn't we use his distance and time, where they are [tex]\frac{x_0}{\gamma(v)}[/tex] and [tex]t_0 \gamma(v)[/tex], and v would be [tex]\frac{x_0}{t_0 \gamma(v)^2}[/tex]. It seems that we're using [tex]x_0[/tex] either [tex]t_0[/tex] and not both, nor none. Isn't this inconsistent?