Cooperative learning, using small groups to complete a common goal, has a positive effect on student achievement and potential in foundational engineering mechanics courses. The purpose of this study was to quantitatively examine the effects of cooperative learning on student performance, if these effects are concept-specific, and perceptions of learning within an introductory Dynamics course. Data were collected from one section of n=55 students. Optional weekly cooperative sessions were offered in addition to in-class traditional lecture. Students who attended cooperative sessions earned 12.8% higher overall grade (p=0.001) specifically attributable to rigid body kinematics (p=0.002) and rigid body kinetics (p=0.001), which is newer and more challenging material for students. Cooperative learning was associated with positive perceptions of learning, with 85-95% of students agreeing that it was helpful towards the understanding of material. Future work aims to incorporate group processing and adaptations for different class sizes.