Answer:
The kinetic energy
Step-by-step explanation:
The potential energy (P) is the energy that the swing has due to its position, and it can be calculated with the expression
P = m . g . h
where,
m: mass
g: gravity
h: height
The higher is the swing, the more potential energy it has.
On the other hand, the kinetic energy (K) is the energy which a body possesses by virtue of being in motion, and it can be calculated using the expression
K = 1/2 . m . v²
where
v: speed
In B, the swing is virtually still (v = 0), while in A, v is maximum and so is its kinetic energy.
Then, as the swing moves from point B to point A, the kinetic energy increases and the potential energy decreases.