85.5 applications of Newton's law Choose horizontal plane as reference frame: NE-N For triangle block of mass M F=nsin 8=Mam F,=Q-Mg-Nc0s6=0(2) 85.5 applications of Newtons law Choose M as the reference frame Fo=-maM+ For block of mass m F=mg sin 0 +mam cos0=ma(3) F=N-mg cos0+ mam sin 0=0(4)18 Choose horizontal plane as reference frame: cos 0 (2) sin (1) = − − = = = θ θ F Q Mg N F N Ma y x M For triangle block of mass M aM r θ M x y N N r v ′ =− Q r W r §5.5 applications of Newton’s law Choose M as the reference frame: cos sin 0 (4) sin cos (3) = − + = = + = ′ θ θ θ θ y M x M F N mg ma F mg ma ma For block of mass m y x a ′ r m F maM r r 0 = − N r W r §5.5 applications of Newton’s law