science high school ngss ps2-1 physics chemistry periodic motion elements 8th grade force vector acceleration torque rotational newton math common core scalar velocity mass si units hs-ps1-1 angular lever 8.ee.4 5.nbt.2 5th grade exponents projectile displacement distance kinematics resultant symbol position element measurements base unit laws rotational motion quantity types rate mathematics two dimension hs-ps1-2 friction 8.ee.7 prefix circular motion symbols speed trajectory centripetal gravity gravitation sliding adding orbit block subtracting