We reviewed Archimedes principle for buoyancy. The buoyant force is equal to the weight of the fluid displaced. The weight of the fluid displaced is the mass of the fluid displaced times g the acceleration due to gravity (9.8 m/s²).

F_buoyant = M_{fluid displaced} * g

The mass of the fluid displaced is the density of the fluid times the volume displaced.

M_{fluid displaced} = ρ_fluid * V_displaced

F_buoyant = ρ_fluid * V_displaced * g

We next discussed the Law of the Lever.

If we place the box of heavy cats farther from the lever's fulcrum, then we can apply less force than the weight of the cats. However, the cats will not move as far as our applied force does. In fact the ratio of forces was equal to the inverse of the lengths from the fulcrum.

F₁ / F₂ = R₂ / R₁

or

F₁ R₁ = F₂ R₂

In our discussion we also mentioned what stayed the same. While force and distance were changing on the different sides of the lever, the work and the torque was the same on both sides.