Activity 86: Investigating Center of Mass Warm up: if your crash-dummy is in an accident and the car comes to stop, what will be the motion of the dummy during the car accident? (Think of Newton’s 1 st law!) A car accelerates down the road. What is the “reaction” to the tires pushing on the road? (Think of Newton’s 3 rd law!)

Activity 86: Investigating Center of Mass When a dummy gets in a car accident, it will continue to move forward until an outside force acts on it. When a car’s tires push on a road, since every action has an equal and opposite reaction, the road will in turn push on the tires.

Activity 85 Analysis Questions

Activity 86: Investigating Center of Mass Please open your books to page E58.

Activity 86: Investigating Center of Mass Center of mass: Sometimes called “center of gravity.” The point or location where the distribution of an object’s mass is centered or even. When an object is in its center of mass, it should not move, but rather stay in equilibrium. What is the center of mass of a meter stick?

Activity 86: Investigating Center of Mass Working with the people at your table, follow the procedure and record the data in the table made in step #2. For your table, add a column for the predictions. Your chart should look like this: MassPredictionObservationStability Ranking Empty cart Loaded cart, low center of mass Loaded cart, higher center of mass

Activity 86: Investigating Center of Mass With your group, answer this question in at least 3 sentences: Why do you think pick-ups and SUVs tend to roll over more often than passenger cars of similar mass? Explain in terms of center of mass. What is the center of mass of a 10-cm thick wheel that has a diameter of 40 cm?

Tonight’s Homework Complete analysis questions #1-4. Start bringing in project materials!