True, a rock with more mass will have more kinetic energy than a rock with less mass when rolling at the same speed.
The kinetic energy (KE) of an object is given by the formula:
\[ KE = \frac{1}{2} mv^2 \]
where \( m \) is the mass of the object and \( v \) is its velocity. If both rocks are rolling at the same speed, the one with the greater mass will indeed have more kinetic energy.