What is the momentum of a proton travelling at v = 0.95c in the x-direction

in the reference frame?

Photons all travel at velocity c in a vacuum, in any reference frame. The momentum depends upon the frequency. This question has no answer.

will I be able to calculate the momentum if I know the mass of the proton?

Is the question assuming the proton is travelling relativistically or not?

p = gamma m v

gamma = 1/sqrt[1-(v/c)^2]

The mass of a photon is zero; yet it has momentum. The momentum (as well as th energy) depends upon the frequency, which you have not provided.

Nat, use what Count Iblis provided.

PS: drwls, the question asks about the momentum of a proton, not a photon.

To calculate the momentum of a proton, we can use the formula:

p = mv

Where:
p is the momentum of the proton,
m is the mass of the proton, and
v is the velocity of the proton.

In this case, we are given that the proton is traveling at v = 0.95c in the x-direction. Since c represents the speed of light in a vacuum, which is approximately 3 x 10^8 meters per second, we can calculate the velocity of the proton:

v = 0.95c = 0.95 * (3 x 10^8 m/s) = 2.85 x 10^8 m/s

Next, we need to determine the mass of the proton. The mass of a proton is approximately 1.67 x 10^-27 kilograms.

Now we can substitute the values into the formula:

p = (1.67 x 10^-27 kg) * (2.85 x 10^8 m/s)

Multiply the values:

p = 4.7595 x 10^-19 kg·m/s

Therefore, the momentum of the proton traveling at v = 0.95c in the x-direction is approximately 4.7595 x 10^-19 kg·m/s.