Physics Exam

[coolguy246]

I think this exam was more difficult in past years (not the type of questions but there were lots of sneaky things here and there). I believe the cut off for A+ will be about 105/130 or so....

[99.95_goal]

7 Ohms. (negative value of the y intercept)
I have a bad feeling like it is out of range though. Also, I am guessing that is the way to find the value, as -R was the 'c' value of the equation linking r and 1/i.

yea that's what I got too, except I just subbed in the i value when r=0 which was 0.3 and times it by 24

[99.95_goal]

7 Ohms. (negative value of the y intercept)
I have a bad feeling like it is out of range though. Also, I am guessing that is the way to find the value, as -R was the 'c' value of the equation linking r and 1/i.

also that 'show that' question for the last one, what were we meant to do? I sorta just did a general equation then subbed in the values for voltage and current but the wording confused me a lot

[schoolstudent115]

also that 'show that' question for the last one, what were we meant to do? I sorta just did a general equation then subbed in the values for voltage and current but the wording confused me a lot

Show: r = 16/i - R (changing the number to 16 in case copyright is an issue)

The input voltage is 16 V.
Current = i = V/Rt  = 16/(r+R), rearranging: r+R=16/i , hence, r = 16/i - R

[99.95_goal]

Show: r = 16/i - R (changing the number to 16 in case copyright is an issue)

The input voltage is 16 V.
Current = i = V/Rt  = 16/(r+R), rearranging: r+R=16/i , hence, r = 16/i - R

Ok, I did that but wasted so much time trying to sub in values like in methods

[schoolstudent115]

What about that question where the electron was in a field and could land at points X, Y or Z?
I chose Z, as if v increases, F = qvB increases, as F is downwards, this will outweigh the electric field induced force, hence the electron will move down to z.