Asubstance that is made of atoms of more than one type bound together is called a

Could someone . i have tried to solve myself but my calculation is off

You are driving directly behind a pickup truck, going at the same speed as the truck. a crate falls from the bed of the truck to the road. (a) will your car hit the crate before the crate hits the road if you neither brake nor swerve? (b) during the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck?

What is an aquifer for science class