Idk if it's correct but I guess it's calcite (c)
1. Potential Energy is stored energy a object has when it's not moving.
2. Potential Energy is it's highest on the first stage because as you see the roller coaster is bout to go down the tract which is going to higher the kinetic energy and lower the potential energy.
3. Kinetic Energy is the amount of energy a object has when it's in motion or moving.
4. Kinetic Energy is it's highest in the third stage after it's gone down the tract and potential energy fully decreased and it's at zero.
Remember that potential energy is stored energy so when a object is not moving in this case the roller coaster isn't moving on the first stage when its bout to go down the roller coaster. Kinetic energy is the amount of energy a object has when it's in motion so in this case the third stage would have the highest example of Kinetic energy because it's fully in motion and has no potential energy.
Answer:
297 J
Explanation:
The key to this problem lies with aluminium's specific heat, which as you know tells you how much heat is needed in order to increase the temperature of 1 g of a given substance by 1∘C.
In your case, aluminium is said to have a specific heat of 0.90Jg∘C.
So, what does that tell you?
In order to increase the temperature of 1 g of aluminium by 1∘C, you need to provide it with 0.90 J of heat.
But remember, this is how much you need to provide for every gram of aluminium in order to increase its temperature by 1∘C. So if you wanted to increase the temperature of 10.0 g of aluminium by 1∘C, you'd have to provide it with
1 gram0.90 J+1 gram0.90 J+ ... +1 gram0.90 J10 times=10×0.90 J
However, you don't want to increase the temperature of the sample by 1∘C, you want to increase it by
ΔT=55∘C−22∘C=33∘C
This means that you're going to have to use that much heat for every degree Celsius you want the temperature to change. You can thus say that
1∘C10×0.90 J+1∘C10×0.90 J+ ... +
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Answer: B. False
Explanation: A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Example:
Thus as we can see sodium ion 
is being replaced by ammonium ions 
and thus positive ions replace positive ions only and not negative ions.
