Vector Sum of Forces Experiment

[Kenny Wong]

Homework Statement

http://cgscomwww.catlin.edu/sauerb/AP12/AP12_Labs/AP12_Lab_4_Forces_files/image002.jpg
My experiment is like this picture found in the net. The weight in the middle is called R in my experiment, while the left one is P and the right Q.

Now there is one question asked, the answer of which is needed to be included in the report.
It goes like this: "the direction of ALL the resultant vector R=( l P+Q l ) must be the same. If you want the direction of the resultant vector R to be different, what should you do to the arrangement of apparatus in Figure 4? (Use your own creativity / creative thinking)"

2. The attempt at a solution
Is the direction of the resultant vector R the same as the gravity which is downwards? Then how can we change it?

 

[CWatters]

Clearly you can't change the direction of gravity but the problem doesn't limit what else you can change. Have a think about gravity and what it is.

 

[Kenny Wong]

OK gravity is always directed towards the centre of the earth.

 

[CWatters]

Gravity yes. What about other forms of acceleration?

 

[Kenny Wong]

There are 4 types of fundamental forces: Gravity, Electromagnetic Force, Strong Nuclear Force and Weak Nuclear Force.
The latter two are, if I am correct, involved particularly in interactions between elementary particles.
So Sir, do you mean electromagnetic force?

I have thought about that but it seems to complex and sophisticated.
Please enlighten me...:)

 

[CWatters]

Those are forces. I said acceleration.

The mass is currently hanging down vertically due to gravity. Can you think of a way to get it to hang at say 10 degrees to the vertical? Hint: You might not be able to do it in a confined space or for very long.

 

[Kenny Wong]

Do you mean tilting the whole table, Sir?
This is the only way I can think of...
and it's the same as decreasing the height of one of the two fixed points (P or Q), if I am not mistaken.

 

[CWatters]

I was actually thinking of putting the rig on wheels and accelerating it horizontally.

 

[Kenny Wong]

Do you mean like this, Sir?
Because I don't really understand...

 

[CWatters]

No I mean put the whole rig on wheels and accelerate it across the lab like this..

 

[Kenny Wong]

OH...
Oh sorry Sir, forgive my stupidity. Yes you have solve the problem! Since day 1...
Thank you Sir CWatters for accompanying me this whole week. I appreciate it. :k

Though in the end, I still can't figure it out myself...