Lecture on SI Units www assignmentpoint com Base

Lecture on SI Units www. assignmentpoint. com

Base Quantity Base Unit Name Symbol Name Time Length Mass Temperature Electric Current Amount of Substance Luminous Intensity t l m T, Ө I n (not in A Level) Symbol second metre kilogram kelvin ampere mol candela cd www. assignmentpoint. com s m kg K A

Physical Quantity Defined as : Unit velocity acceleration density momentum force pressure work (energy) power electrical charge potential difference resistance www. assignmentpoint. com Special Name

Homogenous Equations • Ep = m g h • J = kg Nkg-1 m • Nm = kg kgms-2 kg-1 m • kgms-2 m = kgm 2 s-2 • kgm 2 s-2 = kgm 2 s-2 • This equation is homogenous www. assignmentpoint. com

Homogenous Equations • v 2 = u 2 +2 ax • m 2 s-2 = m 2 s-2 + ms-2 m • m 2 s-2 = m 2 s-2 + m 2 s-2 • This equation is homogenous www. assignmentpoint. com

Homogenous Equations • F = mv r • N = kg ms-1 m-1 • kgms-2 = kgs-1 • This equation is not homogenous www. assignmentpoint. com

Homogenous Equations • What is missing? ms-1 = kgms-2 = kgs-1 v on rhs • The equation should read: • F = mv 2 r www. assignmentpoint. com

Homogenous Equations • Try these: • Ek = ½ m v 2 J = kg m 2 s-2 N m = kg m 2 s-2 OK • and v = u + at 2 ms-1 = ms-1 + ms-2 s 2 ms-1 = ms-1 + m Not OK s-1 is missing, so equation should read: www. assignmentpoint. com V = u + at

Homogenous Equations Homework: Show that these equations are homogenous a) x = ut + ½at 2 b) T = 2π√l/g c) v = fλ d) I = n. Ave e) W = ½CV 2 What is missing here? f) F = mv - mu www. assignmentpoint. com