We are given the velocity of the particle as a function of displacement:
\[
V = \sqrt{196 - 16X}
\]
To find the acceleration, we first recall that acceleration \( a \) is the derivative of velocity with respect to time:
\[
a = \frac{dV}{dt}
\]
Using the chain rule, we can express this as:
\[
a = \frac{dV}{dX} \cdot \frac{dX}{dt} = \frac{dV}{dX} \cdot V
\]
Now, differentiate \( V = \sqrt{196 - 16X} \) with respect to \( X \):
\[
\frac{dV}{dX} = \frac{-8}{\sqrt{196 - 16X}}
\]
Therefore, the acceleration is:
\[
a = \frac{-8}{\sqrt{196 - 16X}} \cdot \sqrt{196 - 16X} = -8 \, \text{m/s}^2
\]
Thus, the acceleration is \( -8 \, \text{m/s}^2 \).
\[
\boxed{-8 \, \text{m/s}^2}
\]