Answer:
a)
Weight in Air = 0.3N
Weight in Water = 0.25N
Weight in Liquid = 0.24N.
Upthrust /Buoyant Force = Weight in Air – Weight in Fluid(Water in this case)
= 0.3 – 0.25
= 0.5N.
b) R.D of Body = Density of Body/Density of Standard Fluid(Water).
There's a Derived Formula for RD.
I'm gonna Apply it here.
Ask me for the derivation in the Comment section if you need it.
RD = α/ρ = (Weight in Air) / (Upthrust Force)
Where
α = density of the Body(or reference substance)
ρ = density of standard fluid (water)
= 0.3/0.05 = 6.
c) RD of Liquid = (Density of Liquid) /(Density of standard Fluid(water)
Or we just go by that formula
RD of Liquid = Weight in Air/Upthrust(In Liquid)
We'll be using the Upthrust in that Liquid now.
= 0.3 – 0.24 = 0.06
RD = 0.3/0.06 = 5.
The fastest speed before the string breaks is 9.5 m/s
Explanation:
The motion of the block is a uniform circular motion, which is a circular motion with constant speed. The force that keeps the block in circular motion is called centripetal force; its direction is towards the centre of the circle and its magnitude is given by:

where
m is the mass of the block
v is its speed
r is the radius of the circle
In this problem, the centripetal force is provided by the tension in the string, T, so we can write:

The string breaks when the centripetal force becomes larger than the maximum tension in the string:

Re-arranging the equation for v,

and here we have:
T = 450 N
m = 10 kg
r = 2 m
Substituting,

So, the fastest speed before the string breaks is 9.5 m/s.
Learn more about circular motion:
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#LearnwithBrainly
Answer:
C) A ratio based on the mass of a carbon-12 atom
Explanation:
For each element, there is a characteristic number of protons, this number represent a type of atom and its called the atomic number
On the other hand we have the number of neutrons, and for one element which difers only on the number of neutrons, we have different isotopes from one element.
Together, protons and neutrons define the mass number
One property linked with the mass number, is the atomic mass, which is formerly expressed as "uma" (atomic mass unit)
By definition, one atom of carbon-12 (with 6 neutrons) has an atomic mass of 12 umas
a) Speed of the Moon: 1025 m/s
The speed of the moon is equal to the ratio between the circumference of its orbit and the orbital period:

where
is the radius of the orbit of the Moon
is the orbital period
Substituting into the formula, we find

b) Centripetal force: 
The centripetal force acting on the Moon is given by:

where
is the mass of the Moon
is its orbital speed
is the radius of the orbit
Substituting into the formula, we find

c) Gravitational force
The only relevant force that acts on the Moon, and that keeps the Moon in circular motion around the Earth, is the gravitational force exerted by the Earth on the Moon. In fact, this force "pulls" the Moon towards the Earth, so towards the centre of the orbit of the Moon, therefore it acts as source of centripetal force for the Moon.
By carefully reading the question, we are able to discern from its wording the fact that Oasis of the Seas is not a submarine. Instead, wherever she sails, she is expected to <em>float</em> on the surface of the briny deep.
A floating object displaces water equal to its own weight.
So the Oasis must displace
(approx 220,000,000 lbs)/(65 lbs/ft³) =
approx <em>3,384,615 ft³</em> of sea water