Answer to Question #112431 in Physics for Ini-obong oraegbu

Question

A non uniform rod X y of mass 40kg and length 5 m lies on the horizontal ground. It's center of gravity is from the end X. Calculate the vertical force p that will be sufficient to lift the end y from the ground why would the force p,if applied at the end X not be sufficient to lift the X from the ground

Answer 1

Taking the moments about the end X:

$$PL-mg(d)=0$$

$$P(5)-(40)(9.8)(2)=0$$

$$P=157\ N.$$

If force P was applied at the end X. Taking the moments about the end Y:

$$M=PL-mg(L-d)$$

$$M=157(5)-(40)(9.8)(5-2)=-391<0$$