- #1
frasifrasi
- 276
- 0
I have this as an online assignment and think I have the wrong answer, but the site is telling me the result is wrong and takes a percentage off my grade each time i send a wrong submission.
I am just posting an image link because that way you guys can see the picture:
http://img142.imageshack.us/my.php?image=screenhunter003xp5qz5.png
Here is what I have so far:
t = length of plates / horizontal velocity
= 2.20 * 10-2 m / 18.0 m/s = 1.22 * 10-3 s
In the same time, the drop must deflect by 'd' distance along vertical direction. By second equation of motion
d = uy * t + (1/2) * ay * t2
uy = initial velocity along vertical direction = 0
ay = acceleration along vertical axis.
=> 0.300 * 10-3 = 0 * t + 0.5 * ay * (1.22 * 10-3)2
ay = 3.0 * 10-4 / 1.49 * 10-6 = 2.01 * 102 m/s2
__________________________________________________________
F = q * E
by Newton's second law F = m * a
=> m * ay = q * E
q = m * ay / E = 1.0 * 10-11 * 2.01 * 102 / 7.90 * 104
q = 2.54 * 10-14 C
But this is wrong and the site won't give me a feedback. If anyone can help me out, I would be very thankful. : )
I am just posting an image link because that way you guys can see the picture:
http://img142.imageshack.us/my.php?image=screenhunter003xp5qz5.png
Here is what I have so far:
t = length of plates / horizontal velocity
= 2.20 * 10-2 m / 18.0 m/s = 1.22 * 10-3 s
In the same time, the drop must deflect by 'd' distance along vertical direction. By second equation of motion
d = uy * t + (1/2) * ay * t2
uy = initial velocity along vertical direction = 0
ay = acceleration along vertical axis.
=> 0.300 * 10-3 = 0 * t + 0.5 * ay * (1.22 * 10-3)2
ay = 3.0 * 10-4 / 1.49 * 10-6 = 2.01 * 102 m/s2
__________________________________________________________
F = q * E
by Newton's second law F = m * a
=> m * ay = q * E
q = m * ay / E = 1.0 * 10-11 * 2.01 * 102 / 7.90 * 104
q = 2.54 * 10-14 C
But this is wrong and the site won't give me a feedback. If anyone can help me out, I would be very thankful. : )