Wednesday, 12 January; Mechanics 3 Examination discussion thread

It's probably someones being weird or has taken an M3 ages ago its a PM exam though (had me worried i missed it!)
All the best everyone. I got 14.00 start time!!

Reply 3

interesting paper methinks

Aaaaaaaaah! :|

shift3

Aaaaaaaaah! :|

How was it?

Euclid.

Reply 6

some examiner likes questions with letters and complicated numbers

Reply 7

Euclid

How was it?

Euclid.

Horrible. I think I'm getting a 25/100. (Had a 74 from June. :frown:

)

Reply 8

Q 1 - circular motion with a tension
Q 2 - Centre of mass cone/hemisphere
Q 3 - Shape y=sinx
Q 4 - SHM fairground game
Q 5 -
Q 6 -
Q 7 - Trapeze artist - circular motion/ energy changes

anyone fill in the gaps and add to?

Reply 9

Q 1 - circular motion with a tension
Q 2 - Centre of mass cone/hemisphere
Q 3 - Shape y=sinx
Q 4 - SHM fairground game
Q 5 - F(t) question
Q 6 -
Q 7 - Trapeze artist - circular motion/ energy changes

Reply 10

rockindemon1

Q 1 - circular motion with a tension
Q 2 - Centre of mass cone/hemisphere
Q 3 - Shape y=sinx
Q 4 - SHM fairground game
Q 5 - Variable acceleration
Q 6 - SHM elastic string
Q 7 - Trapeze artist - circular motion/ energy changes

yeah...

Reply 11

I hated the center of mass questions (last part in both), and q 7. Ugh.

Reply 12

Ack i went in feeling that it would be ok (compared to other stuff on other papers!)
Ended up with a weird answer for mass of the ball.

Reply 13

Gaz031

I really panicked in that exam at the start. Half way through i felt like i wanted to kill myself but gradually think i improved. I felt confident only a few hrs before going in but then almost fell apart.

Q 1 - circular motion with a tension

This was a fairly standard question. Mistakedly i put the angle with the horizontal for part b, but changed it right at the end.

Q 2 - Centre of mass cone/hemisphere

Messed this up at the start twice because i put the radius of the hemisphere as 2r, rather than r. I came back to it at the end, then did the second part. I found the values needed for equilibrium then said equilibrium does not occur and hence reversed the inequality sign (and took away the or equal to condition). Hope that's okay. One part that confused me was i didn't know at first whether the expression was a distance toward the hemisphere or a distance towards the cone.

Q 3 - Shape y=sinx

I started rotating around the x axis at first but quickly realised my mistake and changed it. for the angle did ppl get arctan(pi/2)/(pi/8)=arctan4?

Q 4 - SHM fairground game

Fair enough, a little confusing but i think i got it. For the time you needed to work out you did 2[time], where time was given by 0.5b=asinwt?

Q 5 - Variable acceleration

Standard stuff. The distance was something between 100 and 200? (cant remember)

Q 6 - SHM elastic string

Vmax was something like (5/2)(gl/2)^0.5 ?

Q 7 - Trapeze artist - circular motion/ energy changes

Was a little confused at first but then got it. You had to use conservation of momentum at the bottom. Anyone get m=6?

My exam paper was very untidy, and the second question was at the end because i came back to it. Hope they manage to decipher it.

Why is it that everything that seemed easy outside the exam suddenly makes your nervous and jittery? I guess it's because you know you can't turn and look up your answer to check you got it right =/

Reply 14

lol

I simply made up values... m=3kg, v=13ms^-1, and solved the last part. I didn't want to waste any time thinking up a proper solution. :p:

Reply 15

Yer the answer is 6 (done it now) I put 15 in exam (Argh)

Reply 16

slim786

I got mass as 6 and speeds of 7 and 8m/s for other parts of question. Was distance for kinematics question 162m

Reply 17