Two resistors have resistances r1= ( 24+- 0.5)ohm and r2 = (8 +-0.3)ohm . calculate the absolute error and the percentage relative error in calculating the combination of two resistances when they are in parallel.

An experiment was performed on a 2-kg block. forces of 5, 10 and 15 newtons respectively were applied to the block for 5 seconds. describe the difference in acceleration between the three trials. a) the final accelerations will all be the same. b) the final acceleration will triple between the first and third trial. c) the final acceleration will be cut by 1/3 from the first to third trial. d) the final acceleration will increase nine time between the first and third trial.