Question: Physics problem. Newton's 3rd law

Physics problem. Newton's 3rd law

A 1.54-kg beaker contains 2.67 kg of oil (density= 916 kg/m^3). A 6.27-kg block of iron is suspended from a spring scale and completely submerged in the oil. Note that the force of the oil on the block of iron is upward. By Newton's third law, the force of the block on the oil must then be downward. Find the equilibrium reading of (a) the top scale and (b) the bottom scale. I'm given answer ranges. a) 20.0, 70.0 N and b) 44.0, 50.0 N ---so it would look like a spring scale, with a block hanging from it. The block is in a beaker full of oil, and the beaker is sitting on a scale.

Date Posted: December 01, 2007 Tagged Under: Newton . Newton's third law . buoyant force . Physics
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I don't remember exactly how to do this kind of problem, however I have a basic idea. Maybe it will help.

You would need to set up a Free Body Diagram. Accounting for gravitational force and the normal force which are equal according to Newton's Third Law. The normal force in this case would be due to the oil which can be calculated using Archimedes' principle (for buoyancy). Let me know if this helps.