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# lads can only do this m2 question watch

1. it's 5a first question in heinemann book

a uniform beam AB of mass 20 kg and length 2m is attached to a vertical wall by means of a smooth hinge at A. The beam is maintained in the horizontal psition by means of a light inextensible string, one end of which is attached to the beam at B and the other end is attached to the wall at a point in the wall 2m vertically above A

a) calc T
2. I'll go... T = 139N
Cud be horribly wrong, ill check my genitalia in a moment err!
3. (Original post by YorkshirePhoeni)
I'll go... T = 139N
Cud be horribly wrong, ill check my genitalia in a moment err!
i get t'same
4. ditto;

if you take moments about A, you have:-
20g = 2Tsin45
T= 10g / sin45 = 138.6N
5. wt if tension in string was 400 n n there was a mass at b
wtn is da mass?
6. (Original post by mabs)
wt if tension in string was 400 n n there was a mass at b
wtn is da mass?
Take moments about A again and call the mass at b 'M', you already know the tension so it should come out using the moments equation.
7. everyone knows the method but wots the ansa darlin???
8. (Original post by mabs)
wt if tension in string was 400 n n there was a mass at b
wtn is da mass?
As Mysticmin said, using the same format; Moments about A

20g + 2M = 400 sin 45

2M = 400 sin 45 - 20g

M = (400 sin 45 - 20g)/2

M = 43.4N

Therefore Mass M = 43.4/9.8 = 4.43 kg (Do not forget this step)
9. (Original post by YorkshirePhoeni)
As Mysticmin said, using the same format; Moments about A

20g + 2M = 400 sin 45

2M = 400 sin 45 - 20g

M = (400 sin 45 - 20g)/2

M = 43.4N

Therefore Mass M = 43.4/9.8 = 4.43 kg (Do not forget this step)
I got a different answer by taking moments, ive probably gone wrong somewhere, if so , feel free to point out and **** off!...

moments from A... letting mass at B =B

20gm + 2mBg = 400sin45x2m

remove 2m from all...

10g + Bg = 400sin45
98 + 9.8B = 282
9.8B = 184
B = 18.86 kg
10. Taking moments
===========

2m.Tcos45 - 2m.Mg = 1m.20g
2.400.1/√2 - 2Mg = 20g
Mg = 200√2 - 10g
M = 200√2/g - 10
M = 28.86 - 10
M = 18.86
M = 18.7 kg (3 sf)
========
11. like i sed only men can do m2
12. (Original post by mabs)
===========

M = 18.86
M = 18.7 kg (3 sf)
========
I liked the answer before the strange sig figs...
13. kk georgey

we having fun

girls arre wallowin in self pity
14. (Original post by mabs)
like i sed only men can do m2
Hove you done it yet? what did you get?
15. (Original post by mabs)
like i sed only men can do m2
You've got to be bloody joking. I'm a girl and I have never got below 65/75 in M2.
16. (Original post by Mysticmin)
You've got to be bloody joking. I'm a girl and I have never got below 65/75 in M2.
Do you get the joke or not? lol
17. (Original post by George-W-Duck)
I got a different answer by taking moments, ive probably gone wrong somewhere, if so , feel free to point out and **** off!...

moments from A... letting mass at B =B

20gm + 2mBg = 400sin45x2m

remove 2m from all...

10g + Bg = 400sin45
98 + 9.8B = 282
9.8B = 184
B = 18.86 kg
Oh aye forgot the 2m x the 400 sin 45, else i get the same 18.86
This is the start of my m2 revision i DO apologise!
18. (Original post by glance)
Do you get the joke or not? lol
Nah, I only saw that post, explaination?
19. (Original post by glance)
Do you get the joke or not? lol
I dont' get the joke...explain
20. Maybe there wasn't one. I didn't think it was very funny...anyway, forget that.

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