A rectangular plank of mass .m_(1).and height .a. is on a horizontal surface. On the top of it another rectangular plank of mass .m_2. and height .b. is placed. The potential energy of the system is,

A rectangular plank of mass .m_(1).and height .a. is on a horizontal s

1.	A rectangular plank of mass .m_(1).and height .a. is on a horizontal surface. On the top of it another rectangular plank of mass .m_2. and height .b. is placed. The potential energy of the system is,
Answer» `(m_(1) + m_(2))(a+b)/2 G` `[(m_(1) + m_(2))/2. a + m_(2) b/2]g` `[(m_(1)/2 + m_(2)) a + m_(2) b/2]g` `[(m_(1)/2 + m_(2))a + m_(1)b/2]g` ANSWER :C