Answer:
Most likely, it will be harder to get strong magnets to change phase because they have more density.
gravitational Potential energy is given by

here we have
m = 200 kg
h = 21000 m
now we will have


so GPE of balloon will be 41160000 J above the given height from ground
Answer:Eating. Your muscles in your arms and mouth use energy to feed itself. Then your body digest the food which also takes energy.
Sleep. When your tired, you don’t have much energy. It is said that you use more energy while your sleeping. But how do you become energized if you were using even more energy than before?
The speed of the ball moving is

what is momentum?
The momentum p of a classical object of mass m and velocity v is given by pclassical =mv.
For photons with wavelength λ,this equation does not hold.Instead, the momentum of the Photon is given by p Photon = h/λ
where,h is the planck's constant.
The momentum of the red Photon is
given:




since,the Photon and the ping-pong ball have the same momentum,we have



Therefore, if the red photon and the ping-pong ball have the same momentum, the ping-pong ball must have a speed of approximately

learn more about momentum of photon from here: brainly.com/question/28197406
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