Momentum in Bumper Car Collisions

Begin with the astronaut sheet, where everything starts at rest. Move to bumper cars for collisions, then use the helmet sheet to connect momentum to force.

Work out momentum before and after bumper car collisions, with signs for left and right. The directions on the page read: Use the rule box and the three scenes. For 1 to 6, write your work on the first line and the answer with its sign and units after the equal sign. An answer key is included.

Yes, both. We made it for 8th grade forces and motion, and it works the same at home or at school. At home, a student can work through it alone and then go over it with you, which shows quickly what is solid and what needs another look. In class it works as independent practice, homework or a warm-up, and you can print one copy or a full set.

Multiply mass in kilograms by velocity in meters per second to get kg·m/s. Direction matters, so the bumper car sheet uses plus for right and minus for left. Total momentum is the sum of each object's momentum.

The push and the reaction are equal and opposite, so the two change momentum by equal and opposite amounts. Starting at rest, m₁ × v₁ = m₂ × v₂, so the lighter one moves faster. In orbit there is almost no friction, so each keeps moving.

Average force equals change in momentum divided by stopping time. A longer stop gives a smaller force for the same change in momentum. The helmet sheet uses a 5 kg headform hitting an anvil at 6 m/s.