When a gas is compressed, its particles are pushed closer together so it is more dense.
The gravitational potential energy referred to the ground level is given by

where m is the mass of the object,

is the gravitational acceleration and h is the height of the object with respect to the ground.
Therefore in our problem the potential energy is
<u>Answer
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D. Salt water is denser than freshwater.
<u>Explanation</u>
A boat is able to float on water because it experiences an upthrust upwards.
The magnitude of the upthrust depends on the density of the liquid.
When the liquid is denser the boat will experience a great upthrust as compared to when in a less dense liquid.
If the boat sinks lower in the freshwater than in salty water, then Salt water is more dense than freshwater.
Answer:
Wheel A.
Explanation:
The lesser the moment of inertia, the greater the angular acceleration. Then, the moments of inertia of each wheel are described below:
Wheel A

Wheel B


The wheel A accelerates faster in response to the torque.