<span>So the question is in what did johannes Kepler reject since he believed in the heliocentric universe. So heliocentric system is a system where the sun is in the center of the Solar system. Geocentric system is the system where Earth, not Sun is in the center of our system. He was against Geocentric system. </span>
Answer:
the maximum mass that can hang without sinking is 2.93 kg
Explanation:
Given: details:
sphere diameter d = 20 cm
so, radius r = 10 cm = 0.10 m
density of the Styrofoam sphere D = 300 kg/m3
sphere volume 
=4.18*10^{-3} m^3
we know that
mass M = Density * Volume
= (300)(4.18*10^{-3} m3)
=1.25 kg
mass of the water displace = volume *density of water
= 4.18*10^{-3} m3 * 1000
= 4.18 kg
The difference between the mass of water and mass of styrofoam is the amount of mass that the sphere can support
=4.18 kg -1.25 kg
= 2.93 kg
By heat or change in matter,
there can be different reactions that create heat (like exothermic or endothermic reactions)
or movement can give off energy too,
energy is basically just heat
Answer:
Yes it is possible to control to some extent.
Explanation:
In general there are two types of magnets : permanent and temporary (electromagnets).
Electromagnets can be controlled since it basically depends on electricity. By switching on and off the electric supply the magnets also can be switched on and off respectively. We can also control the intensity of magnetic power.
On the other hand permanent magnet cannot be switched on and off but the magnetic properties can be altered event to an extent when it loses all its magnetic properties. It can be caused by high temperature, physical impact and also exposure to other magnetic fields. For every element there is a point of temperature called curie temperature above which the permanent magnet loses its magnetic properties. This can be brought back again by induced magnetism. The only issue is that induced magnetism work in most cases but not in all.
Please find attached photograph for your answer.
Hope it helps.
Do comment if you have any query.
