Question

A block of wood weighs 160 N and has a specific gravity of 0.60. To sink it in fresh water requires an additional downward force of:_______A. 54N B. 64N C. 96N D. 110N E. 240N

Answer 1

Answer:

Your answer is: D) 110N

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Explanation:

In order for the wood to sink, it's specific gravity must equal 1 (or greater).

Specific gravity = .6 kg/m^3= Mass/volume

F (Newtons or kg x m/s^2) = Mass*9.8m/s^2.  

Therefore, Mass = 160 N / 9.8 m/s^2= 16.32 kg

Volume = Mass/Specific Gravity = 16.32kg/.6 kg/m^3 = 27.2 m^3

Desired Specific gravity = 1 = (Mass + additional force/9.8m/s^2)/Volume = (16.32 kg +X / 9.8m/s^2)/27.2m^3

Solving for the additional force: X = 106.66...N

The answer is D, 110 N will be required to sink the block of wood.