Resolution of Forces?

• Nov 9th 2005, 04:36 PM
amans1ngh
Resolution of Forces?
Right im soo stuck its i feel like im banging into a brick all over and over again... and this is in for 14.00 tommo :cry:

Was wondering if anyone can help me work out how to do this in the most simplest form please!

The procedure...

1. Assemble a 3 spring balance system making sure that each spring is sufficiently loaded.

2. Place a piece of paper at the common load point.

3. Carefully trace the angular relationship between the loads.

4. Record the loads indicated by the spring balances.

5. Resolve any of the two forces in the direction of the third force.

6. Resolve any of the two forces in the direction perpendicular to the third force.

7. Compare the calculated forces with measured values.

8. Discuss the results indicating any discrepancies.

Ok well thats basically what I had to do... im am comfortable up until step 4... now my question is can anyone explain to me how to work out the resolution of forces on this? Please be as simple as possible as i need to do the same thing on a four load system.

• Jun 12th 2008, 07:58 PM
malaygoel
Hi!
First some nomenclature.
Let the point where three forces meet is "O".
Let the point where you have written 3N be A.
Mark a point B on line AO such that A and B are on opposite sides of O.
Mark a point C on the light line going upwards(line adjacent to dark line of 9N)
Mark a point D on OC such that C and D are on oppsite sides of O.
Let 3N force be the third force.(since you have drawn coordinate axes along that force)

Now we resolve 9N force.
If you resolve this force along the co-ordinate axes, you will see that one component will be in the direction of OB and other in the direction of OC.
We require the component in the direction OB.
Now, the force vector of 9N force makes 96deg. angle with OA.
Hence it makes 84deg. angle with OB. So, its component along OB is 9N*cos(84deg.)

Now we resolve 8.1N force.
This force will be resolved along OB and OD.
The angle here is 76deg.(160-84 or 180-104). Hence component is 8.1N*cos(76deg.)

Keep Smiling
Malay