Answer:
av=0.333m/s, U=3.3466J
b.

Explanation:
a. let
be the mass of block A, and
be the mass of block B. The initial velocity of A,
-The initial momentum =Final momentum since there's no external net forces.

Relative velocity before and after collision have the same magnitude but opposite direction (for elastic collisions):

-Applying the conservation of momentum. The blocks have the same velocity after collision:

#Total Mechanical energy before and after the elastic collision is equal:

Hence, the maxumim energy stored is U=3.3466J, and the velocity=0.333m/s
b. Taking the end collision:
From a above, 
We plug these values in the equation:


Answer:
People can capture geothermal energy through: Geothermal power plants, which use heat from deep inside the Earth to generate steam to make electricity. Geothermal heat pumps, which tap into heat close to the Earth's surface to heat water or provide heat for buildings
When the weather is cold, the water or refrigerant heats up as it travels through the part of the loop that's buried underground. Once it gets back above ground, the warmed water or refrigerant transfers heat into the building. The water or refrigerant cools down after its heat is transferred.
The repeated rising and sinking of water during boiling is due to convection. It <span>is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it. Hope this answers the question.</span>
From the formula: density=mass/volume
But first, we have to convert the cm³ to m³ by multiplying the value in cm³ by 10^-6, by so doing we'll have the volume to be 0.48*10^-3cm³.
we will also need to convert the mass which is in g to kg by simply dividing by 1000 so the mass becomes 0.12kg
Now we can solve for the density using the formula I earlier stated which is the mass divided by the volume =0.12/0.48*10^-3 so the density will be 0.25*10^3kgm-3 or 2.5*10^2kgm-3
Friction I believe is the answer
hope this helps