Final answer:
A proton and an electron moving at the same speed and direction respond differently to the same electric and magnetic fields due to their opposite charges and different masses. The direction of the magnetic forces is opposite for each particle, and the electron experiences a larger acceleration.
Step-by-step explanation:
When a proton and an electron are moving at the same speed in the positive x direction and then experience both an electric field and a magnetic field pointing in the positive z direction, their behaviors differ due to their charges and masses.
The magnetic force acting on both the proton and the electron has the same magnitude since they possess charges of equal magnitude but opposite signs. According to the right-hand rule for the proton and the left-hand rule for the electron, the direction of the magnetic force will be opposite for each particle: the proton's magnetic force will be in the negative y direction, and the electrons will be in the positive y direction.
Both particles will also experience electric forces, but in opposite directions due to their opposite charges. As a result, they will have accelerations opposite in direction. Due to its smaller mass, the electron will experience a larger acceleration compared to the proton when the same electric and magnetic forces are applied.
In conclusion, the proton and electron will both curve in their paths due to the magnetic force but in opposite directions, and the acceleration due to the electric force will be greater for the electron.