Aplant falls from a window ledge 3.5 m above the sidewalk. how fast is the plant moving when it hits the sidewalk?

The motion of the plant is a free-fall motion, with acceleration a=g=9.81 m/s^2, so we can use the following relationship:

where S=3.5 m is the distance covered by the plant from the window to the sidewalk, vf is the final speed and vi=0 is the initial speed of the plant.

Substituting numbers, we can find the value of the speed when the plant hits the ground:

Multiply the 3 dimensions, assuming it is a rectangular cuboid, to get the volume in cm³ divide mass by volume to get density in g/cm³