Help with M1 question?

It's hard for me to visualise things in mechanics, which makes it difficult for me to visualise and answer questions. This is M1 vectors. I don't want just the answer, I would really appreciate an explanation or formula or some form of working with this question because I'm not sure how to approach it.

'The diagram shows three forces which act in the same plane and are in equilibrium, where a =6n and b = 7n.
A) find F
B) find (alpha)'

Any help appreciated, thanks


Posted from TSR Mobile

OK, firstly do you know what it means for a vector to have components? Do you know how to work out the components of force vector F in the horizontal and vertical directions?

Not at all. In my most recent post I explain how I literally know nothing but basic vector knowledge and how to work out the magnitude and direction angle. If you could explain what components of vectors are it would be so helpful. Thank you


Posted from TSR Mobile

OK, well your teacher or textbook should really have explained this to you first, but basically you can split any vector into components in perpendicular directions (for example the conventional x- and y-directions going left to right and bottom to top).

So your vector F has a component that acts horizontally and a component that acts vertically,

Now, I'm sure you can see that if you had just 2 forces acting on something, say a force pulling to the left and force pulling to the right, they would have to be equal in order for the thing to stay where it was.

So the horizontal component of F must equal the force pulling to the left, and the vertical (upwards) component of F must equal the force acting downwards.

When you have a force F at an angle X (I'll use this instead of alpha to save typing!) to the horizontal, then the horizontal component of F is FcosX and the vertical component is FsinX.

So you should be able to write down 2 equations involving F that represent the fact that the forces are all balanced:

FcosX = something
FsinX = something else

Hope this helps, but do grab an M1 textbook because all this is much clearer with a good diagram!

Thank you! I understand all you've explained. I shall try and work it out from here although I have no angle values. Thanks again


Posted from TSR Mobile

Working out the angle is part B

Write down your 2 equations involving F and alpha, and think about what you might do to try to work out the value of F.

Thanks! By the way, I know I posted twice but the other was less detailed, I shall delete the post. Thanks again for your help.


Posted from TSR Mobile