Which o the following phrases bet describes a physical model?

a. an exact copy of an object, system, or process
b. a chemical formula
c. a graph or equation
d. a representation of an object, system, or process

2) a cubical block of stone is lowered at a steady rate into the ocean by a crane, always keeping the top and bottom faces horizontal. which one of the following graphs best describes the buoyant force b on this block as a function of time t if the block just enters the water at time t = 0 s?