Question

# An FBI agent orders a block of ballistics gel. The gel weighs 54 pounds per cubic foot. What is the weight of the block of gel?

Solid Geometry
An FBI agent orders a block of ballistics gel. The gel weighs 54 pounds per cubic foot. What is the weight of the block of gel?

2021-05-18

First, we find the volume of the gel which is a rectangular prism in shape: $$V=lwh$$
$$V=(20)(6)(6)$$
$$V=720$$ cubic inches
Then, we convert this cubic foot. Since $$1 ft = 12 in$$., then $$(1 ft)^3 = (12 in.)^3$$ or $$1 ft^3 = 1728 in.^3$$ so:
$$V=720$$ cubic inches $$\times$$(1 cubic foot/1728 cubic inches)$$=\frac{5}{12}$$ cubic foot
We find the weight of the gel by multiplying the density by the volume:
(54 pounds/cubic foot)$$\times\frac{5}{12}$$ cubic foot=22.5 pounds