Inertia

​What is Inertia?

By Stephanie Ramirez

1. Why does reducing friction help moving objects?

2. Why does a box of bricks move less than a box of feathers?

3. In a crash, why does the dummy keep moving forward?

4. How do seatbelts and airbags change motion?

Multiple Choice

1. What happens when friction increases on a moving object?

• A. The object speeds up

• B. The object’s forces become balanced

• C. The object slows down

• D. The object gains inertia

Multiple Choice

2. Why do engineers try to reduce friction?

• A. To make objects heavier

• B. To keep forces unbalanced

• C. To help objects move more easily

• D. To increase inertia

Multiple Choice

3. A more massive object has…

• A. Less inertia

• B. More inertia

• C. No inertia

• D. Equal inertia

Multiple Choice

4. Why does the crash dummy keep moving when the car stops?

• A. Friction

• B. Balanced forces

• C. Air resistance

• D. Inertia

Multiple Choice

5. How does an airbag reduce injury?

• A. Increases inertia

• B. Reduces friction

• C. Applies an unbalanced force more gently

• D. Makes the dummy move faster