" 20 m/s² " means that if gravity is the ONLY force on the object
(the object is in 'free fall'), then its speed increases by 20 m/s
every second.
That's the answer to your question. Now, let me ask you
another one:
How does a speedometer tied to a falling rock work ?
How can it measure the rock's speed ?
Maybe one way would be to have a little tiny propeller on
the front of the speedometer, and it could measure how fast
the propeller is spinning as the rock falls through the air ?
Great idea. But we already said the rock is in free-fall,
so there's no air resistance, we can't have any air, and
there's nothing to spin the propeller.
How would you do it ? How can you measure the rock's speed ?
I really don’t know but I hope this helps
Answer:
Potential energy plus kinetic energy equals mechanical energy because mechanical energy is basically just all of an object's energy, it's just two kinds of energy. The potential is stored inside and kinetic is being used. Both of those together is the total amount of the objects energy, which is the mechanical energy.
Explanation:
Distance = (speed) x (time)
Distance = (20 m/s) x (500 s)
Distance = (20 x 500) (m·s / s)
Distance = 10,000 m
The radius of the cylinder is equal to half the diameter:

The volume of the cylinder is given by:

where h is the heigth of the cylinder. Converting into meters,

And the density of the material will be given by the ratio between the mass and the volume:
