M1 Moments

Which part are you stuck on?

Reply 2

OP

Original post by Student403

Which part are you stuck on?

so far i've drawn a beam with 3g at one end and 1g on the other, in the centre i've put 4g going down and i've labelled the distances as 1m from 4g to either side of the beam

Reply 3

Original post by thefatone

so far i've drawn a beam with 3g at one end and 1g on the other, in the centre i've put 4g going down and i've labelled the distances as 1m from 4g to either side of the beam

Draw the pivot and add a reaction force from the pivot as well. Then take moments from one of the ends. You'll need to resolve vertically to find the reaction force from the pivot.

Reply 4

Original post by thefatone

so far i've drawn a beam with 3g at one end and 1g on the other, in the centre i've put 4g going down and i've labelled the distances as 1m from 4g to either side of the beam

Good going :smile:

Now you need to remember that since there's one pivot, the reaction force upwards is equal to the entire weight of everything downwards from the beam. What's the exact value of that?

Also, why don't you let x = the distance of the pivot from a chosen end. Then you could take moments from that end to find the value of x

Reply 5

OP

Original post by Zacken

Draw the pivot and add a reaction force from the pivot as well. Then take moments from one of the ends. You'll need to resolve vertically to find the reaction force from the pivot.

Original post by Student403

Good going :smile:

Now you need to remember that since there's one pivot, the reaction force upwards is equal to the entire weight of everything downwards from the beam. What's the exact value of that?

Also, why don't you let x = the distance of the pivot from a chosen end. Then you could take moments from that end to find the value of x

there's a pivot? o.o that's at the 4g right? i guess that's what i was missing >.>

Reply 6

Original post by thefatone

A uniform beam of length 2m and mass 4kg has a mass 3kg attached at one end and a mass of 1kg at the other end. Find position of the pivot if the beam rests in equilibrium in a horizontal position.

help.... this is due in 2 hours and 5 minutes from the time of this post @TeeEm @Zacken @Student403

Reply 7

Original post by thefatone

there's a pivot? o.o that's at the 4g right?

No, they're asking you to find the position of the pivot, see my diagram.

Reply 8

Original post by thefatone

there's a pivot? o.o that's at the 4g right? i guess that's what i was missing >.>

No the pivot is where you have to work out. See Zain's drawing

Reply 9

Original post by Zacken

No, they're asking you to find the position of the pivot, see my diagram.

Damn you've beat me 2/2 times :rofl:

Reply 10

Original post by Student403

Damn you've beat me 2/2 times :rofl:

Nah, you got the first post. :rofl:

Edit: wait for TeeEm's comment. :wink:

Reply 11

Original post by Zacken

Nah, you got the first post. :rofl:

Edit: wait for TeeEm's comment. :wink:

Aww bless!

Reply 12

OP

Original post by Zacken

right oh okay the question is phrased slightly different to how i would normally see them in the textbook, usually in the textbook they call the unknown distance x or something Thanks a bunch

Reply 13

Original post by thefatone

right oh okay the question is phrased slightly different to how i would normally see them in the textbook, usually in the textbook they call the unknown distance x or something Thanks a bunch

Good questions are when they are unstructured and you need to pick your own variables and label your own stuff. I prefer those kinds of questions, you'll need to get used to it. :tongue:

No problem! :-)

Reply 14

OP