Share Your Favourite Private Messages! - Page 3

I might have sent you half a pm. I hit tab + enter by an accident. Ignore that other PM if you got it.

Try to absorb what I'm saying. This shit is easy and I don't think you're getting it, you're just reading the answers and not thinking. SHITS EASY SON.

1.) Seriously kid; Go to fucking school and listen to the fucking teacher. This shit is so easy and you should have learned it in grade 10 physics on the second day.

Get out a ruler and protractor. Draw an arrow at length 40 and angle 45. From the end of that arrow, draw a line length 20 and angle 90. From the end of that arrow, draw a line length 25, angle 135. Now, from the start of the first arrow to the tip of the last arrow, draw a bold line. Measure the length and angle of that line. That's your answer.

2.) Find the resultant of 40.0 N at 45 degrees, 20 N at 90 degrees and 25 N at 135 degress graphically. (Don't have to draw, I just need instructions on solving this problem.)

Pick a positive and negative direction. For us, up is +Y, down is -Y, right is +X and left is -X. 0 degrees will start along +X and will rotate counter clockwise (so 90 degrees is along the +Y). You don't have to do it like this, BUT MAKE SURE YOU PICK AN AXIS SYSTEM BEFORE YOU START.

MAKE SURE YOU UNDERSTAND COS AND SIN BEFORE YOU START.

Break all the forces into X and Y components. This should be easy:

F1X = 40 cos 45 = 28.28
F1Y = 40 sin 45 = 28.28

F2X = 20 cos 90 = 0
F2Y = 20 sin 90 = 20

Now, for things greater than 90, you can either use the trig circle (ACTS or w/e) (DONT DO THIS), or you can use logic. JUST USE YOUR BRAIN INSTEAD OF MEMORIZING RETARDED "tricks". The thing is 135 degrees counter clockwise from +x. That means it's going to be positive Y and negative X. If you don't understand this, stop reading and draw it until you do.

Therefore,
F3X = -25 cos 45 = -17.68
F3X = 25 sin 45 = 17.68

Now, add all that shit up.
FsumX = 28.28 + 0 - 17.68 = 10.6
FsumY = 28.28 + 20 + 17.68 = 65.96

Nows a good time to ask your teacher how they want the answer.
Some want it in cartesian in which case:
Fresultant = (10.6X + 65.96Y) N is the answer

Some want it in polar, so you have to find the hypotenuse and angle:
Ftotal = root (10.6^2+65.96^2) = 66.8
Angle = arctan (65.96/10.6) = 80.8 (might be wrong, google calculator sucks for using degrees and not radians).
Fresultant = 66.8N at an angle of 80.8 degrees.