Physics Q help

[inaccensa]

2 questions from EK physics- Lecture 5 ( In class Exam)

103- A 2 kg bject submerged in the unknown fluid( specific gravity- 5) has an apparent loss of mass 0.5 kg. What is the specific gravity of the object?

110- If a gold ball spins in the direction opposite the one shown in the figure, the ball will experience

Can anyone please explain these answers. I'm really confused.

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[Isoprop]

For the first one:

Here are my symbols: pf, po, pw are densities of fluid, object, wand water
sf and sw are specific gravities of fluid and object

The loss of weight comes from the bouyant force.
B = (pf)Vg

We know B = mg = 0.5*g = 5N
pf = sf*pw = 5pw (from the definition of specific heat rearranged)
V = m/po = 2/po (from density equation)

Thus, 5 = (5*pw)(2/po)g
Rearrange the equation to get po on one side and the 5's cancel out:
po = pw*2*g

specific gravity of object = po/pw, thus the final answer is

s = po/pw = (pw*2*g)/pw
s = 2g = 20

 

[Isoprop]

And I can't really help you with the second one w/o more information.

 

[fizzgig]

i second the answer to the first question. i was too wussy to write it down.