An experiment is conducted to determine how the arm length of a pendulum effects its period. the experimental design calls for varying the length of the arm and the mass of the bob. which is true about this experiment, based on good experimental design? a. only the arm length should be changed. the mass should remain the same. b. the force applied to the mass should be varied for trial. c. the material the arm is made of should be varied for each trial. d. only the mass should be changed. the arm length should remain the same

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.