On the ground is a rectangular cast-iron slab, base area – 1.5 m2, thickness – 20 cm, find the mass.

S = 1.5 m ^ 2 – base area of a rectangular cast iron plate;

l = 20 centimeters = 0.2 meters – the thickness of the cast iron plate;

ro = 7000 kg / m ^ 3 – density of cast iron.

It is required to determine the mass of the cast iron plate m (kilogram).

Since, according to the condition of the problem, the slab has a rectangular shape, we find its volume:

V = S * l = 1.5 * 0.2 = 0.3 cubic meters.

Then the mass of the cast iron plate will be equal to:

m = ro * V = 7000 * 0.3 = 2100 kilograms.

Answer: The mass of a cast iron plate is 2,100 kilograms (2.1 tons).