Step 1:

The weight density of the concrete is 140.7 pounds per cubic foot.

The depth of the concrete form is 4 ft.

The length of the concrete form is 6 ft.

The depth of the concrete form at a particular point is .

Force exerted is , where is the weight density, is the depth at a point, is the length at a point.

Force exerted on the concrete form is 

Force exerted on the concrete form is pounds.

Solution:

Force exerted on the concrete form is pounds.