Answer:
State your hypothesis as concisely, and to the point, as possible. A hypothesis is usually written in a form where it proposes that, if something is done, then something else will occur. Usually, you don't want to state a hypothesis as a question. You believe in something, and you're seeking to prove it.
Explanation:
As we know that gravitational potential energy is given by

here we have
m = mass = 120 kg

h = height = 8.2 m
now from above formula


so above is the gravitational potential energy of the couch
Answer:
Archimedes' principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially, is equal to the weight of the fluid that the body displaces. Archimedes' principle is a law of physics fundamental to fluid mechanics.
Harder. Not compressible(unless using an extremely strong force). Non-metal have more of a chance of breaking than metals.