Answer:
DETAILS IN THE QUESTION INSUFFICIENT TO ANSWER
Explanation:
Assuming the liquid to be water ,
the density 
of water is : 
Buoyant force exerted by a liquid on an object with 
of it's volume immersed is :
where ,
is the buoyant force
is the density of the liquid
is the acceleration due to gravity
Thus at equilibrium:
from these , we get the density of brass to be 
which is not possible
Answer: The observing friend will the swimmer moving at a speed of 0.25 m/s.
Explanation:
- Let <em>S</em> be the speed of the swimmer, given as 1.25 m/s
- Let
be the speed of the river's current given as 1.00 m/s.
- Note that this speed is the magnitude of the velocity which is a vector quantity.
- The direction of the swimmer is upstream.
Hence the resultant velocity is given as, 
= S — S 0
= 1.25 — 1
= 0.25 m/s.
Therefore, the observing friend will see the swimmer moving at a speed of 0.25 m/s due to resistance produced by the current of the river.
Of the materials listed wood is the best insulator. It would be the least hot if exposed to similar temperatures.
F= MA
force equals mass time acceleration
250 N = (70 kg ) (A)
250/70 = 3.5 which is about 4 m/s
Hope this helps
