B. Inertia and gravity must be balanced.
The answer is A. The kinetic energy
The answer to the question is b because acid is a substance that tastes sour, reacts with metal and turns litmus paper blue
It is 10.20 m from the ground.
<u>Explanation:</u>
<u>Given:</u>
m = 0.5 kg
PE = 50 J
We know that the Potential energy is calculated by the formula:

where m is the is mass in kg; g is acceleration due to gravity which is 9.8 m/s and h is height in meters.
PE is the Potential Energy.
Potential Energy is the amount of energy stored when an object is stationary.
Here, if we substitute the values in the formula, we get

50 = 0.5 × 9.8 × h
50 = 4.9 × h

h = 10.20 m