Two wooden boxes of equal mass but different density are held beneath the surface of a large container of water. Box A has a smaller average density than box B. When the boxes are released, they accelerate upward to the surface. Which box has the greater acceleration?

Box A

Explanation:

Let mass of each wooden box =m

Density of box A=

Density of box B =

Density,

Density of inversely proportional to volume.

The volume of box with smaller density is larger than the volume of box with large density.

When the boxes are submerged under water.

Then, the buoyant force=

Where V=Volume of displace fluid.

Density of fluid

Buoyant force of box A=

Buoyant force of box  B=

Force=Buoyant force

Acceleration is directly proportional to volume.

Therefore,the box with large volume has greater acceleration.

Hence, the box A has greater acceleration.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.