Vertical Deflection of Electron: 1.1×107 m/s & 3.2×10-16 N

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An electron moving horizontally at a speed of 1.1 × 10^7 m/s is subjected to a vertical force of 3.2 × 10^-16 N, prompting discussions on how to calculate its vertical deflection over a horizontal distance of 34 mm. Participants emphasize the importance of treating horizontal and vertical motions separately, noting that the vertical force does not influence horizontal speed. The acceleration due to the vertical force is calculated, and the time of travel is determined using the horizontal motion. The final vertical distance is computed using kinematic equations, leading to a significant deflection value, which prompts discussions about unit accuracy. The conversation highlights key physics concepts, including the effects of force on velocity and the separation of motion components.
  • #31
If we instead consider the position of a particle I mentioned earlier. If we keep the x co-ordinate constant, but changed the y co-ordinate, the direction we would need to travel in order to reach the particle has changed. It doesn't mean the x co-ordinate has.

Do you see how we can relate this to the velocities?
 
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  • #32
Stephen Hodgson said:
If we instead consider the position of a particle I mentioned earlier. If we keep the x co-ordinate constant, but changed the y co-ordinate, the direction we would need to travel in order to reach the particle has changed. It doesn't mean the x co-ordinate has.

Do you see how we can relate this to the velocities?
i see know
 
  • #33
J-dizzal said:
maybe not, if there are no forces acting in the -x direction, then the x component of its velocity doesn't change. its only the y component increasing right?
Exactly! :smile: The y component is increasing, thus changing the direction. The x component does not need to change for this to happen
 
  • #34
So the x velocity is constant. What equation can we therefore use to calculate the time the particle is in motion for?
 
  • #35
Stephen Hodgson said:
If we instead consider the position of a particle I mentioned earlier. If we keep the x co-ordinate constant, but changed the y co-ordinate, the direction we would need to travel in order to reach the particle has changed. It doesn't mean the x co-ordinate has.

Do you see how we can relate this to the velocities?
so
Stephen Hodgson said:
Exactly! :smile: The y component is increasing, thus changing the direction. The x component does not need to change for this to happen
Stephen Hodgson said:
So the x velocity is constant. What equation can we therefore use to calculate the time the particle is in motion for?
t=dist/v = 3.091x10-9s
 
  • #36
That seems correct to me.

We now need to use that time to calculate the vertical distance travelled.
 
  • #37
Stephen Hodgson said:
That seems correct to me.

We now need to use that time to calculate the vertical distance travelled.
yes just distance now. so Δy = v0t - 1/2 at2 this look like a good formula of motion to use?
 
  • #38
This looks good.

What values of v, a and t are you going to use?
 
  • #39
Stephen Hodgson said:
This looks good.

What values of v, a and t are you going to use?
v0=0, a= 3.5126x1014, and t=3.091x10-9
 
  • #40
Great! v0 should be 0 because in the y direction it is initially at rest :smile:.

You may want to check your equation again though. Are you sure about the - sign?

Let me know what you get as your final answer.
 
  • #41
Stephen Hodgson said:
Great! v0 should be 0 because in the y direction it is initially at rest :smile:.

You may want to check your equation again though. Are you sure about the - sign?

Let me know what you get as your final answer.
542872.33 m that seems huge. yea i rechecked formula thanks its + because v is the unknown not v0
 
  • #42
Stephen Hodgson said:
Great! v0 should be 0 because in the y direction it is initially at rest :smile:.

You may want to check your equation again though. Are you sure about the - sign?

Let me know what you get as your final answer.
542872.33 m seems large
 
  • #43
J-dizzal said:
542872.33 m seems large
forgot to sqare the time one sec
 
  • #44
1.678 m
 
  • #45
Almost. Check your units.
 
  • #46
Stephen Hodgson said:
Almost. Check your units.
1.67810^-3
 
  • #47
lol thanks
 
  • #48
Great! Glad I could help. It seems like you learned a lot doing that question :smile:
 
  • #50
Stephen Hodgson said:
Great! Glad I could help. It seems like you learned a lot doing that question :smile:
yea i learned some fundamental concepts that i know will help on the exam
 
  • #51
main thing being that force changes the velocity of a particles seems so obvious now
 
  • #52
Yeah. The other important thing is to know that you can simply treat the velocities separately. It is often easier to do this than try to work with vectors.
 
  • #53
I just had a look at the circular motion problem. Which part are you having problems with?
 
  • #54
Stephen Hodgson said:
I just had a look at the circular motion problem. Which part are you having problems with?
i can't seem to find any unknowns. i know that 3/4 of the distance of the circle is traveled by the particle in 9.90s-3.30s but when i try to derive an equation for total time(T) i cant. to solve for T i have so far 6.6T = 3pi/2 but plugging that solution into r =vt/2pi its to get the radius its not working
 
  • #55
So is the y co-ordinate obvious from your diagram?

To calculate T, a bit of common sense needs to be used. If 3/4 of the circle is completed in 6.6s, how long does it take to complete a full circle?
 
  • #56
Stephen Hodgson said:
So is the y co-ordinate obvious from your diagram?

To calculate T, a bit of common sense needs to be used. If 3/4 of the circle is completed in 6.6s, how long does it take to complete a full circle?
8.8s would be the whole right?
the y coordinate of?
 
  • #57
Stephen Hodgson said:
So is the y co-ordinate obvious from your diagram?

To calculate T, a bit of common sense needs to be used. If 3/4 of the circle is completed in 6.6s, how long does it take to complete a full circle?
ok 8.8 works, it must of made a mistake in the math last time i tried it.
 
  • #58
So that question is now solved?
 
  • #59
Stephen Hodgson said:
So that question is now solved?
just working on the y coordinate now
 
  • #60
Take a look at your diagram.
 

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