4-C. ... 5-D. ... 6-A. ... 7-D. ... 8-C. ... 9-B. ... 10-D. It's really a joy and a delight that you've learned so much by posting all of these questions.
Heat required to raise the temperature of mercury is given as

here given that
m = 56 g
s = specific heat capacity of mercury = 0.140 J/g C

now here we have


so it required 2265.76 J of heat
Answer:
a)
, b) 
Explanation:
a) According the Archimedes' Principle, the buoyancy force is equal to the displaced weight of surrounding liquid. The mass of the coal in the barge is:




b) The submersion height is found by using the equation derived previously:


The final submersion height is:

Assuming it starts at rest, the roller coaster only has potential energy at the top of the hill, which is

When it reaches the bottom, its potential energy will have converted to kinetic energy,

where
is its velocity at that point. By the law of conservation of energy, assuming no loss of energy due to other sources (e.g. sound, heat), we have

