How is this done and what would be the answer? truss forces for engineering

Typically a point in a three dimensional cartesian coordinate system is represented by which of the following answers in the picture !

The height above the ground (in feet) of a ball dropped from the top of a 30-foot-tall building after t seconds is given by the polynomial: ? 16t^2+30 what is the height of the ball after 1/2 second?

You work for a landscape company that just got a contract to re-mulch a park. the area that needs mulching is 30 feet by 60 feet. they want a 3 inch layer of much on the area. the company has bags of mulch that cover 2 cubic yards that cost $4.00 per bag. how much will it cost the consumer just in materials to re-mulch the area (round to the nearest dollar)?