Answer
(2), (1), (3)
Work Step by Step
We were given the rest energy and total energy, respectively ,of three particles, expressed in terms
of a basic amount A as (1) A, 2A; (2) A, 3A; (3) 3A, 4A.
Without calculations, we want to rank them according to their speed; greatest first.
The Lorentz factor is based on the speed paramter, $\beta$,
$$\gamma=1/\sqrt{1-\beta^2}$$
We can see that the greater the Lorentz factor is, the greater the speed parameter is.
We know from the previous part (8c) that particle (2) has the greatest Lorentz factor, followed by (1), and then (3). Our answer to this part will be the same
