To viktige korreksjoner/oppklaringer

Jeg legger forel?pig ikke ut ny versjon, men limer inn endringen her:

I oppgave 2B.4, punkt 11, s? skal teksten lyde:

Repeat point 7 above using $m_C = m_A + m_B$ instead of the number for $m_C$ given in the video. This time, do not insert numbers, but keep symbols to arrive at $v_A'$ and $v_B'$. Can the total mass actually equal the sum of the masses? This result will be very important when we will discuss nuclear reactions.

I prosjekt, part 8, punkt 1 p? tillegget til 2B.3 p? slutten s? skal teksten lyde:

We will again imagine a stick with the two laser beams as end points. Your task is now to find the length of the stick $L'$ measured in the space ship frame, expressed only in terms of the length $L$ in the planet frame and the relative velocity $v$ between the frames. You should use invariance of the space time interval, but you need to define the events yourself: you need only two events. You may choose to synchronize the clocks when the first beam is emitted. In addition you also need the equation for the position of the first light beam as a function of time in both systems. Knowing the position of the space ship and the light beam in both systems will give you $L$ and $L'$.