I know the answer is a = - g/ (1 + I/mR^2) but I dont know how to get there?
-la/R^2 - mg = ma
-mg = ma + la/R^2 (Add both sides by la/R^2)
-mg = a(m + l/R^2) (Factor the a on the right-hand side)
-g = a(1 + l/mR^2) (Divide both sides by m)
-g/(1 + l/mR^2) = a (Divide both sides by 1 + l/mR^2).
Comments
-la/R^2 - mg = ma
-mg = ma + la/R^2 (Add both sides by la/R^2)
-mg = a(m + l/R^2) (Factor the a on the right-hand side)
-g = a(1 + l/mR^2) (Divide both sides by m)
-g/(1 + l/mR^2) = a (Divide both sides by 1 + l/mR^2).