00:01
In this problem, we are solving for electric fields.
00:08
We're solving problems involving electric fields and regarding the motion of charged particles that are inside or entering electric fields.
00:21
In this case, we have a proton, which is a charged particle, that moves at a given speed.
00:27
It has a starting velocity in the horizontal direction.
00:32
And then it enters a uniform electric field with the given magnitude.
00:39
We have three parts.
00:41
For the part, they mean to find the time interval, which is required for the proton to travel five centimeters horizontally.
00:49
So from standard kinematics, we know that the displacement in this case, horizontal or the pad traveled, is equal to the velocity in that direction.
01:04
Initial in this case, times the time.
01:09
Therefore, the velocity, or in this case we need to find the time, is equal to the displacement over the velocity.
01:20
Now we know both the displacement and velocity, so we can substitute, and when we substitute this value into a calculator, we obtain that this is equal to or 1 .11 times 10 to the 7 power seconds.
01:50
In this case, we transform the result into nanoseconds, since it is more convenient this way.
02:02
For the part b, we need to find acceleration.
02:05
Now, from the second unit is law, we know that force is equal to the acceleration times the mass.
02:12
In this case, it is the mass of the proton.
02:14
And force, force is the electric force.
02:17
So we can say that charge of the proton times the intensity of the uniform electric field is equal to the acceleration of the proton times its mass.
02:31
Therefore, the acceleration equals charge of the proton times, the electric field over the mass of the proton.
02:42
And all these values are known so we can substitute their bodies...