Floating piece of wood - buoyancy question.?
a piece of wood is floating in a tub with a second piece of wood sitting on top of it without touching the water. if the second piece of wood is now taken off the first and placed in the water, will the water level of the tub change? -prove the answer is correct by using archimedes principle in an analytical argument. note: i really have no idea how to answer this question or do this problem, you in advance!

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

An object weigh 40n in air ,weigh 20n when submerged in water,and 30n when submerged in a liquid of unknown liquid density.what is the density of unknown of liquid?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?