course PHY 121
Prof. SmithI am trying to calculate the degrees for the experiment in assign. 18. For 2 dominoes I have a force of .38N. The length of my rubber band at this force is 8.8cm. I can't take ds * N because that is not going to give me degrees. The block of dominoes moved .8cm. Do I take the .8 and subtract it from the 8.8cm? I am trying to find degrees so I can't use sin or cos, I am not sure what to do.
You don't need degrees for this calculation. Degrees measure angular displacement. You are asked as part of this experiment to estimate and report the degrees of rotation of the domino, but that estimate doesn't figure into this calculation.
What you want to calculate here is the average force exerted by the rubber band, multiplied by the distance over which the force is exerted. If the rubber band has an initial unstretched length of, say, 8.1 cm, then it would have stretched from 8.1 cm to 8.8 cm while exerting forces that increased from 0 N to .38 N. Assuming that the force increases linearly with stretch, which is more or less so for a rubber band, this implies an average force of (0 + .38 N) / 2 = .19 N. Multiplying this force by the distance through which the rubber band exerts it, you would get for this calculation
work = .19 N * .7 cm = .133 N cm.