Edexcel A-level Further Mechanics 2 - 25th June 2019 [Exam Discussion]

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Reply 40

mmonk

thx so much, this was a massive help,

Original post by Anon4012

Bit rough but hope this helps, ask away if not clear :smile:

Reply 41

mmonk

can someone please explain why a string needs tension>0 to complete vertical circles but a bead or rod only needs velocity>0
???? thanks

Reply 42

TarekHelmy

guys where can i find further mechanics 2 papers??

Reply 43

TarekHelmy

if the string does not have tension when its moving in a circle it will be slack and wont complete the circle, however since beads dont go slack all they need is speed to over come gravitational force and form a circle

Original post by mmonk

can someone please explain why a string needs tension>0 to complete vertical circles but a bead or rod only needs velocity>0
???? thanks

Reply 44

Anon4012

A string still needs tension otherwise it would not be following circular motion - i.e. even if it had velocity, you don't know it is still in circular motion so you need to know that R or T > 0 (depending on the case) to show the particle is either still in contact with circular object or the string is still taught and in circular motion. If this is not the case and there is still velocity, the particle would be travelling as a projectile.

When a particle is connected to a rod, naturally if it has sufficient velocity it will make the full circle as it cannot go 'slack', therefore you only need to verify v>0 at the top.

Original post by mmonk

can someone please explain why a string needs tension>0 to complete vertical circles but a bead or rod only needs velocity>0
???? thanks

Reply 45

mmonk

thanks guys, if t>0 does that mean v>0?

Reply 46

TarekHelmy

yes because there would be no tension if there is no force from the circular motion which requires speed

Original post by mmonk

thanks guys, if t>0 does that mean v>0?

Reply 47

TarekHelmy

guys you dont have papers?

Reply 48

mmonk

there doesnt seem to be a lot of resources for this exam,
shame

Original post by TarekHelmy

guys you dont have papers?

Reply 49

TarekHelmy

Original post by mmonk

there doesnt seem to be a lot of resources for this exam,
shame

Ripp

Reply 50

buckmoo

How did people find the exam? I did not understand how to do the shm...

Reply 51

boi_

Got 3,4,5 couldn’t do much of 6,7 and I got v close on 2 and I think I got 1 idek

Original post by buckmoo

How did people find the exam? I did not understand how to do the shm...

Reply 52

username3228632

Not bad but yh the SHM was weird. What did you guys get for the angles?

(a) angle for 1/4 (X-2)^2 or whatever it was as it hangs
(b) angle for cylinder and y^2=2x body on a slope

Original post by buckmoo

How did people find the exam? I did not understand how to do the shm...

Reply 53

DeBrevitateVitae

Very standard exam. Questions reflected difficulty of average of the M3 papers from old spec very well. Overall I'm pleased with what I managed.
Did anyone else write 'acceleration perpendicular because tangential acceleration only since no centripetal force'? I went on to say that although there is a component of weight along the rod, there is a thrust/ reaction from the rod on the bead at the point of contact.

Reply 54

heteromorphic

29.2 and 38.2 degrees respectively

Original post by Peegs

Not bad but yh the SHM was weird. What did you guys get for the angles?

(a) angle for 1/4 (X-2)^2 or whatever it was as it hangs
(b) angle for cylinder and y^2=2x body on a slope