 # 6 Forces in Equilibrium

This is a unit where you can really go to town on the problems with the vectors. You must read the specification carefully and make sure that you don’t panic if you can’t do all the problems in the post. I have included lots of vector problems which go 360° where the exam board will tend to stick to 90° only to make it easier. However, I am in the business of teaching vectors in 2D and would say I would be a bad teacher to stop just because the exam board don’t do it. You will need the skills found here if you carry on to a Physics type job later on so why not learn now. Most students say it is really hard at first but then the exam is easy and they get it after a bit of graft!

Also you may find it hard to understand the idea that…

1. A diagonal vector can be split into two parts the horizontal and vertical parts which can be treated separately.
2. Two forces can be added together to make a resultant.
3. An object not moving has a sum of all vertical forces as zero and also all horizontal forces as zero.

If you find this is hard keep going as it will click!

#### Resources

6.1 Vectors and Scalars

6.1 Trig Problems (You must have these trig skills before you start the problems)

Unit_7_Statics_Dynamics_Vectors_1 (Easy problems sheet)

6_1_Wires Example (This is an example of resolving – hanging a picture)

Unit_7_Statics_Dynamics_Vectors_2 (Rock Hard Problems Sheet beyond AS/A2)

6.2 Balanced Forces

6_2_Resultant Forces Problems (quick fun problems – no answers)

72_Practical_Coplanar_Forces (practical proving coplanar forces)

6.3 The principle of moments

6_3_Density_of_Ruler_Prac (Use moments to find out density of ruler)

6.4 More on moments

6_4_Bridge_Crane_Prac (Practical showing support forces)

6_4_Putting_Your_Foot_Down_Extension (Nice but more complex sheet on moments in your feet)

## M13a Introduction to Forces. Part 1 of 4. Weight

Introductory lesson in a series of lessons about force. Provides a brief introduction to the study of forces and then discusses 'weight'. Subsequent parts of the lesson will deal with ...normal reaction, friction and tension/compression.[+] Show More