course Phy 241
In the assignment19 experiment under Torques Produced by Forces Not at Right Angles to the Rod you are asked to find the angles in reference to the horizontal. Below it gives directions on how to tell if sine and cosine are negative or positive. It reads ""The sine is negative if the y component is to the left, positive if the y component is to the right."" I do not understand how you know if it is negative and positive and what reference point we are talking about if a y coordinate is left or right from. For cosine it reads "" The cosine is negative if the x component is downward, positive if the x component is upward.
There was obviously an editing error when I wrote the lab. Those lines should (and now that you've pointed out the error they do) read
You earlier found the lengths of the x and y legs of the triangle whose hypotenuse was the length of rubber band system A.
The magnitude of the sine of the angle for the system the y component divided by the hypotenuse, i.e., the ratio of the y component to the hypotenuse. The sine is negative if the y component downward, positive if the y component is upward.
The magnitude of the cosine of the angle for the system the x component divided by the hypotenuse, i.e., the ratio of the x component to the hypotenuse. The cosine is negative if the x component is to the left, positive if the x component is to the right.
Find the sine and cosine for this system.
Using the same method find the sine and the cosine for system B and system C. Ideally system B will be acting vertically, so the cosine will be 0 and the sine will be 1; your measurements might or might not indicate a slight divergence from this ideal.