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Hey there everyone, I had a minor personal revelation while studying physics the other day...
It may just be that I was an idiot in the first place but I always got mixed up when i was quickly trying to figure out component vectors from angles for inclined planes, pulling weights with a rope, projectile motion....
All of a sudden I realized all I needed to do was think of sin90 and cos90 which are 1 and 0 respectively. So if the question involved an angle and I wanted to know whether the equation would involve sin or cos I would think if this angle were 90 degrees would I then get the maximum vector (sin) or the mimimum vector (cos)
Ex: Trying to find the component vector from gravity in the direction down the inclined plane... well if you made the angle 90 degree that means the plane is no longer an incline but rather a vertical drop making the vector down the plane maximum (or all of gravity) there for you need sin because sin 90 is 1.
And then when you're pulling a box with a rope at some angle to the ground to determine the component vector actually doing work on the box (pulling it parallel to the ground) If you made the angle between the rope and the ground 90 degrees) it would go straight into the air meaning you aren't pulling the box forward at all you're just pulling it up.... so you want a vector of 0.... and cos90 is zero so you know to use cos for Work done by pulling a rope at an angle....
It applied to projectile motion, pendulums and anything else with sin and cos involved. This may not be news to people lol but I always tried to just remember whether I'd use cos or sin based on the equation.... and would get mixed up.... and then when I'd try to check it with sohcahtoa..... I would waste time and this whole sin 90 cos 90 stuff has sped up any angle physics I do quite a bit.... hope this helps anyone that may have the same problems.
It may just be that I was an idiot in the first place but I always got mixed up when i was quickly trying to figure out component vectors from angles for inclined planes, pulling weights with a rope, projectile motion....
All of a sudden I realized all I needed to do was think of sin90 and cos90 which are 1 and 0 respectively. So if the question involved an angle and I wanted to know whether the equation would involve sin or cos I would think if this angle were 90 degrees would I then get the maximum vector (sin) or the mimimum vector (cos)
Ex: Trying to find the component vector from gravity in the direction down the inclined plane... well if you made the angle 90 degree that means the plane is no longer an incline but rather a vertical drop making the vector down the plane maximum (or all of gravity) there for you need sin because sin 90 is 1.
And then when you're pulling a box with a rope at some angle to the ground to determine the component vector actually doing work on the box (pulling it parallel to the ground) If you made the angle between the rope and the ground 90 degrees) it would go straight into the air meaning you aren't pulling the box forward at all you're just pulling it up.... so you want a vector of 0.... and cos90 is zero so you know to use cos for Work done by pulling a rope at an angle....
It applied to projectile motion, pendulums and anything else with sin and cos involved. This may not be news to people lol but I always tried to just remember whether I'd use cos or sin based on the equation.... and would get mixed up.... and then when I'd try to check it with sohcahtoa..... I would waste time and this whole sin 90 cos 90 stuff has sped up any angle physics I do quite a bit.... hope this helps anyone that may have the same problems.
