Two priors in Typical nucleus, for example, the relative strength of these forces would be strong(relative strength =1) electromagnetic( 10 weak(10); gravitational (103) In fact, everything we study about ordinary mechanical systems involves only two force cIralviry and elecirorgacnetisrn Tension forces Normal forces Friction forcesTwo protons in typical nucleus, for example, the relative strength of these forces would be: strong (relative strength = ); electromagnetic( ); weak ( ); gravitational ( ). 2 10 − 38 10 9 − 10− 1 In fact, everything we study about ordinary mechanical systems involves only two force: gravity and electromagnetism.  Tension forces Friction forces Normal forces