# UnitForces: Mass and Momentum

### Summary

In this unit, students explore the concepts of mass, center of mass, equilibrium, and stability by exploring how objects balance. Students learn about linear momentum — movement in a straight line —and demonstrate conservation of momentum in collisions between objects of different masses. In associated literacy activities, students apply center of mass and the psychological phenomenon of momentum.

### Engineering Connection

Engineers apply the concepts of mass, center of mass, equilibrium, and stability to safely design structures (auditoriums, shopping malls) and crafts (airplanes, cruise ships, kayaks). This is especially important for structures that may be impacted by heavy loads or natural phenomena like hurricanes or earthquakes. Engineers apply knowledge about momentum and collisions so they can design products with safety in mind. For example, engineers design cars with crumple zones—areas of the car that absorb the momentum of the forces hitting the car—and airbags to protect passengers by accounting for the conservation of momentum.

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### Unit Schedule

Suggested order of activities:

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