Answer:
The speed of the proton relative to the laboratory frame is 0.981c
Step-by-step explanation:
Given that,
Speed of electron v= 0.90c
Speed of proton u= 0.70c
We need to calculate the speed of the proton relative to the laboratory frame
Using formula of speed

Where, u = speed of the proton relative to the electron
v = speed of electron relative to the laboratory frame
Put the value into the formula



Hence, The speed of the proton relative to the laboratory frame is 0.981c