thats ho wi understand VA being at a 45 degree angle to the vertical through V?!!
Seems like too big of an angle to be 45 doesn't it?
How about if you extend the vertical all the way down and consider the acute one angle between VA and it. That's what the mark scheme is doing and what all of these types of questions will refer to most of the time when they say 'angle to the vertical'
Seems like too big of an angle to be 45 doesn't it?
How about if you extend the vertical all the way down and consider the acute one angle between VA and it. That's what the mark scheme is doing and what all of these types of questions will refer to most of the time when they say 'angle to the vertical'
Seems like too big of an angle to be 45 doesn't it?
How about if you extend the vertical all the way down and consider the acute one angle between VA and it. That's what the mark scheme is doing and what all of these types of questions will refer to most of the time when they say 'angle to the vertical'
ok, so I see the angle between V and VA is 45. now, we're taking moments about V do we spin it around in a vertical way, or do we spin around V horizontally, so that B makes a full circle?
ok, so I see the angle between V and VA is 45. now, we're taking moments about V do we spin it around in a vertical way, or do we spin around V horizontally, so that B makes a full circle?
Er... there's no spinning mate.
There are two forces Mg and kMg with a certain perpendicular distance away from the vertical and you need to know what that is.
Taking moments about V with the thing being in equilibrium means that these moments cancel out. Moment = Force x perp. distance
The object is in equilibrium and attached so it is not moving.
the exam solutions guy used to talk about spinning in either clockwise or anticlockwise when referring to moments in M1. what happens when you take moments about a point - how do you visualise whats happening?
the exam solutions guy used to talk about spinning in either clockwise or anticlockwise when referring to moments in M1. what happens when you take moments about a point - how do you visualise whats happening?
Oh I see - I don't teach it like that. For students who struggle with moments I get them to lay a pencil on the force and then calculate the perpendicular distance from the pivot and then it also should be easier to see whether its effect is clockwise or anticlockwise.
Oh I see - I don't teach it like that. For students who struggle with moments I get them to lay a pencil on the force and then calculate the perpendicular distance from the pivot and then it also should be easier to see whether its effect is clockwise or anticlockwise.
I drew a diagram, attached above. is it the perp force from the vertical or from V (where its attached)? oi guess, the larger perp distance, equates to direction of moment (clockwise, etc)? is this wasnt in eq, would it be spinning and creating a circle around V?
thats how exam solutions guy taught it in M1. so what does it mean take by taking moments about V - if its not spinning?
is the diagram correct? how do I calculate the perp distances? thanks
Use the right angled triangle joining your blue line to V and the one joining the green line to V. You can work out the angles in these using the 45 degrees and the angle in the triangle with sides a and 2a.
Use these to work out the lengths of the blue and green lines and then take moments about V.