Question

An electron moving at 0.992c collides head-on with a positron moving at 0.981c. Both speeds are measured relative to the lab.

(a) What is the speed of the positron in the frame of the electron?

(b) How does the speed of the electron in the frame of the positron compare to your pervious answer?

Answer 1

• velocity of the partical in frame s` be vx` is given by
• 

(a) -- given that , vx = 0.981c , v = 0.992c

• putting the values
• 
• 
• ......................(answer)

(b) -- now for this case v = 0.992c , vx = 0.981c

• 
• 
• 
• ............(answer)
• as from above it clear that the speed of positron in the electron`s frame is just opposite to the speed of the electron in the positron fame .