Answer:

Explanation:
Close to Earth's surface, the force of gravity that pulls an object towards the ground is
(2)
where
m is the mass of the object
g is the acceleration due to gravity, which is
close to Earth's surface
This is an approximation of the general formula of gravity valid only close to Earth's surface. The more general formula is
(1)
where
G is the gravitational constant
M is the Earth's mass
m is the object's mass
r is the distance of the object from Earth's center
At the Earth's surface,
r = R (Earth's radius), and by calling the following factor

we see that eq.(1) becomes eq.(2).
Answer:
answer is 2 option because more force is applied
Wow ! This one could have some twists and turns in it.
Fasten your seat belt. It's going to be a boompy ride.
-- The buoyant force is precisely the missing <em>30N</em> .
-- In order to calculate the density of the frewium sample, we need to know
its mass and its volume. Then, density = mass/volume .
-- From the weight of the sample in air, we can closely calculate its mass.
Weight = (mass) x (gravity)
185N = (mass) x (9.81 m/s²)
Mass = (185N) / (9.81 m/s²) = <u>18.858 kilograms of frewium</u>
-- For its volume, we need to calculate the volume of the displaced water.
The buoyant force is equal to the weight of displaced water, and the
density of water is about 1 gram per cm³. So the volume of the
displaced water (in cm³) is the same as the number of grams in it.
The weight of the displaced water is 30N, and weight = (mass) (gravity).
30N = (mass of the displaced water) x (9.81 m/s²)
Mass = (30N) / (9.81 m/s²) = 3.058 kilograms
Volume of displaced water = <u>3,058 cm³</u>
Finally, density of the frewium sample = (mass)/(volume)
Density = (18,858 grams) / (3,058 cm³) = <em>6.167 gm/cm³</em> (rounded)
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I'm thinking that this must be the hard way to do it,
because I noticed that
(weight in air) / (buoyant force) = 185N / 30N = <u>6.1666...</u>
So apparently . . .
(density of a sample) / (density of water) =
(weight of the sample in air) / (buoyant force in water) .
I never knew that, but it's a good factoid to keep in my tool-box.
Kinetic energy=1/2mv^2
=1/2(142*10^-3)(42.9)^2=130.6=131J