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