An 8 kg metal block of dimensions 16 cm xx 8 cm xx 6 cm is lying on a table with its face of largest area touching the table. If g = 10 m s^(-2), the minimum amount of work done in making it stand with its length vertical is

An 8 kg metal block of dimensions 16 cm xx 8 cm xx 6 cm is lying on a

1.	An 8 kg metal block of dimensions 16 cm xx 8 cm xx 6 cm is lying on a table with its face of largest area touching the table. If g = 10 m s^(-2), the minimum amount of work done in making it stand with its length vertical is
Answer» `0.4 J` `6.4 J` `4J` `12.8 J` Solution :When face of the largest AREA is touching the table, height of centre of gravity above the table `h_1 = 6/2 = 3 cm` With its length vertical, height of centre of gravity would become `h_2 = 16/2 = 8 cm` Minimum work required `W = (P.E.)_(2) - (P.E.)_(1) = MG(h_2 - h_1)` `:. W = (8 xx 10(8 - 3))/(100) = 4J` .