Use photomath. I would really recommend it! Hope this helps!
Answer:
84672 J
Explanation:
From the question given above, the following data were obtained:
Height (h) = 72 m
Combined mass (m) = 120 Kg
Acceleration due to gravity (g) = 9.8 m/s²
Energy (E) =?
We can obtain the energy by using the following formula:
E = mgh
Where
E => is the energy.
g => is the acceleration due to gravity
m => is the mass.
h => is the height.
E = 120 × 9.8 × 72
E = 84672 J
Thus, the energy is 84672 J
The answer is (B).
Hope this helps :).
Given information : Sample of 
We need to find the moles of Chlorine in the given sample.
We can say that we need to find moles from the given atoms.
Relation between mole and atom is given by : 
Where
is Avogadro number.


On solving the above equation , atoms(unit) gets cancelled out and we get 0.0286 mol.
In the given sample the moles of Chlorine (Cl) is 0.0286 mol , so option A is correct.