Forces and Trig - Intro to Physics

[SaurabhBhavsar]

The question is when to use sine and cosine.
Sine (sin) Function:
You use sin when you're interested in the component of a force or velocity to the direction you're analyzing.
For example, if you have a force acting at an angle to the horizontal and you want to find the vertical component of that force, you use
sin because it relates the opposite side of a right triangle to the hypotenuse.
Similarly, if an object is moving along a curved path and you're interested in the component of its velocity perpendicular to the path, you would use
sin.
calculation:
Sin (30') = Opposite/hypotenuse
Opposite (FRy) = Sin 30' x 100N = 0.5 x100 =50 N

You use cos when you're interested in the component of a force or velocity to the direction you're analyzing.
For example, if you have a force acting at an angle to the horizontal and you want to find the horizontal component of that force, you use
cos because it relates the adjacent side of a right triangle to the hypotenuse.
Similarly, if an object is moving along a curved path and you're interested in the component of its velocity parallel to the path, you would use
cos.
calculation:
Cos (30') = Adjacent/hypotenuse
Adjacent (FRx) = Cos 30' x 100N = 0.8660 x100 = 86.60 N

[aureeel]

from watching youtube I think I might know the answer. So we know that Fr is the hypotenuse of the triangle that has the force of 100 N and alpha is 30 degrees. FrX is adjacent and FrY is opposite. We want to know what is FrX, because it's the adjacent side and we have information about the hyopotenuse we gotta use cosine to find FrX cause cos=adjacent/hypotenuse and sin for FrY. Frx= cos 30 . 100 N = 50 root 3 N and FrY= sin 30 . 100 N= 50 N (sorry for my bad english, its not my native language)

[knbcejj]

100 sin 30°= 50N

using Pythagora's theorem:
(100)^2 = (50)^2 + (base)^2
10, 000-2500 = base^2
86.6N =base

[devonhansen]

I get FrY= 50N and FrX=86.6N. Law of Sines.

[justinabbott]

I'll be honest, i was off a bit the first try.

[FirstnameLastname-ngjw]

Youre voice is so annoying mate but thanks this was very helpful