mechanics paper 51

[fathimaash]

yeah since you'll have half the value i used on both sides of the equation
6sin45 X r=W X OG

Xactly its still da same..

 

[terrible]

expected gt???

 

[terrible]

for question 3 how to show particle about to lose contact????

 

[lisaann]

for question 3 how to show particle about to lose contact????

You'll show that the normal reaction=0

 

[terrible]

You'll show that the normal reaction=0

how???

 

[lisaann]

By taking the sigma of forces in y direction the equation will cancel leaving R on a side of the equation=0

 

[terrible]

still didn't get it??
there was extension of 0.2

 

[lisaann]

T=lambda(X)/l
then you find the angle T makes with the vertical
you know that the length of string was 0.8 and the height of A above B was 0.6 so you find the angle T makes with vertical and resolve

 

[terrible]

i was going to do the same thing but time was up

 

[iKhaled]

umm guys remember that question where u had to find the weight of the lamina in the first page..i think it was the second part of the question..was the lamina hinged at A or not ? from where we had to take moments ?

 

[lisaann]

About O.

 

[iKhaled]

About O.

why not A ?

 

[kavysista]

Emmm
what did you get for q2 ?
the centre of mass of semicircle was 1/3PIE ?
and the angle was 40 or 30 something like dat ?

gt da same ,hope its dat...

 

[*MK*skydiver :D]

I

why not A ?

I think it's about A , wasn't it hanged about A ?

 

[*MK*skydiver :D]

Was it 1 ?

You did it 1 !! YES YES YES ! I did it 1 too , do u think that's right ?
I did the EPE in P's first position as zero ,and in the second position EPE=(lambda.0.3square)/1.4 and got 1 ,but the answer being a whole number , nd "one" ,wasn't very convincing for mechanics (A) I expected decimals , as usual .............and the mu (u) in the nxt part was 0.5 ,isnt it ?

I spent more than 15 mins on this Q alone (A)

 

[iKhaled]

I
I think it's about A , wasn't it hanged about A ?

it was hinged at A when it was at an angle to the vertical but then in the second part they said its back to its original position vertically..does that mean its not hinged anymore? really i got confused :S

 

[*MK*skydiver :D]

it was hinged at A when it was at an angle to the vertical but then in the second part they said its back to its original position vertically..does that mean its not hinged anymore? really i got confused :S

it was about A (or B maybe) but not about O because this is how it looked lyk >>>

D


so CoM about A

 

[iKhaled]

it was about A (or B maybe) but not about O because this is how it looked lyk >>>

D


so CoM about A

looked like what ?

 

[lisaann]

You can take moments about any point.....
the semi circle was vertical on a plane and the 6N force applied at point (A) point of contact was at an angle 45...
so if u take it about A that force would cancel and you wont be able to find the weight..

 

[iKhaled]

You can take moments about any point.....
the semi circle was vertical on a plane and the 6N force applied at point (A) point of contact was at an angle 45...
so if u take it about A that force would cancel and you wont be able to find the weight..

lisan remember the lamina was hinged..but in the next part of the question when we were asked to find the the weight of the lamina it wasn't hinged right ? or what ? was it still hinged at point A ? :S:S