Step 1: Recall the formula for kinetic energy. The kinetic energy (K.E.) of an object is given by the formula: $$K.E. = \frac{1}{2} m v^2$$ where $m$ is the mass and $v$ is the speed. Step 2: Rearrange the formula to solve for speed squared ($v^2$). Multiply both sides by 2: $$2 K.E. = m v^2$$ Divide both sides by $m$: $$v^2 = \frac{2 K.E.}{m}$$ Step 3: Analyze the relationship between speed and mass. The problem states that the car and the truck have the same kinetic energy. This means K.E. is constant for both vehicles. Also, 2 is a constant. Therefore, we can see that $v^2$ is inversely proportional to $m$: $$v^2 \propto \frac{1}{m}$$ This implies that if the mass ($m$) is smaller, the speed squared ($v^2$) must be larger to maintain the same kinetic energy. Consequently, the speed ($v$) will also be larger. Step 4: Apply the relationship to the car and truck. We are given that the truck has more mass than the car. Since $v^2 \propto \frac{1}{m}$, the object with less mass will have a greater speed. The car has less mass than the truck. Therefore, the car has greater speed. The car has greater speed. $$\boxed{\text{The car}}$$