# Multiple choice answers (1 Viewer)

#### 00iCon

##### Member
For Future Reference:

MOST WIN EVER you should go into the textbook industry!
wow i made some stupid fucking mistakes

also q2 according to all text books man has made centripetal force is 9.8 m/s towards the earth

question 4 is D due to the vx component (how the hell else would it have gone further)

question 5 i have no idea i naturally assumed since the moon orbits around the earth the sun would still have no impact at all considering the moon is in line with the sun every day and it plays no effect on it to my understanding....

9 i thought was C because according to the right hand principal the current would be induced towards the P side (THE CURRENT IS POSITIVE) thus the electrons would all head over to the R side

15 is B because an electric field goes from + to - and thus the work done to put the particle in position P is the greatest

feel free to argue
Q2 is calculatable from infromation given so 9.37.... i.e. (A)
4 is D
5 is C
9 i got C, this is being debated
15 is A: E field is uniform.

#### Ostentatious

##### jfK1c45g2f4Of56Eyd4f57cxZ
About 15, I realised also that it goes from Positive to Negative but then I looked at Q and thought that there's no way that it could be zero, as there is still some magnitude of electric field at that point.

#### Ostentatious

##### jfK1c45g2f4Of56Eyd4f57cxZ
MOST WIN EVER you should go into the textbook industry!
Thank you! If I do, I hope my textbooks end up being the most useful!

#### GT03

##### New Member
MOST WIN EVER you should go into the textbook industry!

Q2 is calculatable from infromation given so 9.37.... i.e. (A)
4 is D
5 is C
9 i got C, this is being debated
15 is A: E field is uniform.
no i think 5 is b. look at the force formula. gravitational force on the moon due to the sun would decrease with increasing distance...

#### patrick little

##### New Member
well, in 11, (D) starts at zero, so wrong. its not asking for the force perpendicular to the coil, but the force ONLY on AB.

for 13 i got B but im not too sure...
Im not that good at physics... But... Im pretty sure that for question 11 in MC it is D because... torque is a function with cos(theta) in it and force is a function with sin(theta) in it... this means that when one is at zero, the other must be at its peak... the only one on there that fits this is D

#### Ostentatious

##### jfK1c45g2f4Of56Eyd4f57cxZ
can i ask the reason for question 4? I spent half an hour checking the maths with it and im not sure if its a or d. if v=u+at, for vertical u=0, meaning t=v/a. since d said arrive at same time but different velocities, could it be not true since at the same instant time velocities would have to be the same? that said for horizontal x=ut, so i guessed smaller time meant less distance...
The answer to 4 is D, as all other quantities except for horizontal velocity are different. Therefore, they fall vertically at the same rate, hitting the ground simultaneously and land with different Resultant Velocities, as their horizontal velocities are different.

#### Ostentatious

##### jfK1c45g2f4Of56Eyd4f57cxZ
Im not that good at physics... But... Im pretty sure that for question 11 in MC it is D because... torque is a function with cos(theta) in it and force is a function with sin(theta) in it... this means that when one is at zero, the other must be at its peak... the only one on there that fits this is D

#### kieranjackson91

##### New Member
1 C
2 A
3 C
4 D
5 C
6 A
7 C
8 C
9 C
10 B
11 D <- wrong
12 D
13 B
14 C
15 A

nice work. but its 13/15.
9
is
A

#### AnandDNA

##### Member
can i ask the reason for question 4? I spent half an hour checking the maths with it and im not sure if its a or d. if v=u+at, for vertical u=0, meaning t=v/a. since d said arrive at same time but different velocities, could it be not true since at the same instant time velocities would have to be the same? that said for horizontal x=ut, so i guessed smaller time meant less distance...

s=ut+0.5at^2

initial velocity is 0 as xsin0=0

hence s=0.5at^2

as s is the same for both projectiles and a is constant, time will be the same.

#### d_liu

##### New Member
Hey why isnt Q1 B, because doesnt the speed not change relative to the planet, and dirction changes, but relative to another planet the speed changes thats what i thought, coz like the slingshot effect, when a satellite swings by it changes direction and gains speed relative to the Sun but NOT the planet..im not sure..

#### 00iCon

##### Member
no i think 5 is b. look at the force formula. gravitational force on the moon due to the sun would decrease with increasing distance...
but the distance change of the moon when it's in front and behing is so small considering the solar system... could be could be not... idk 13/15 now

#### 6tgyuio

##### New Member
oh i guess that would make 4 d, i was happy though since that was my worst problem and I was happy with the rest. For those with medical physics, was that the most straightforward question ever?!

#### 00iCon

##### Member
nice work. but its 13/15.
9
is
A
and what degree qualifies you to make that (incorrect) assumption?

#### Ostentatious

##### jfK1c45g2f4Of56Eyd4f57cxZ
More Future Reference:

#### Joustah

##### New Member
and what degree qualifies you to make that (incorrect) assumption?
Induced current opposes motion of conductor, so palm points the opposite direction of motion. fingers point into page, as the field is into the page. that makes your thumb point to the right. but, current is opposite direction of electrons, so electrons go the the left, to side P. that makes the answer A, at least by my working...

#### cd285

##### Member
someone explain to me why q2 is a? i did the mv^2/r formula and got c....

#### Ostentatious

##### jfK1c45g2f4Of56Eyd4f57cxZ
Hey why isnt Q1 B, because doesnt the speed not change relative to the planet, and dirction changes, but relative to another planet the speed changes thats what i thought, coz like the slingshot effect, when a satellite swings by it changes direction and gains speed relative to the Sun but NOT the planet..im not sure..
Speed changes because the gravitational field slows it down as it drags it in, but due to the slingshot effect, as the probe leaves the planet, it gains some of the planet's orbital/rotational velocity. Due to the conservation of momentum, this means that the velocity of the PROBE changes, and the velocity of the planet decreases. However, the change is insignificant because of the size of the probe in comparison to the planet.

#### Ostentatious

##### jfK1c45g2f4Of56Eyd4f57cxZ
someone explain to me why q2 is a? i did the mv^2/r formula and got c....
v2/r = acceleration in circular motion. If you subbed in m you may have gotten it wrong.

Reasoning:

F = ma
F = (mv2)/r

equating,

v2/r = a

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