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5. Collisions and inertia: Bumper cars

Bumper cars

Go to Tuta & Kör in the Rabbit land  (length restrictions: 90-140 cm) or to the larger Radiobilarna (length restriction: ≥130 cm)  

How does it feel when 

  • the car starts ? 
  • when you drive into another car? 
  • when you are hit from the back? 
  • when you are hit from the side? 
  • when you press the brakes?

Then consider what forces from the car act on you to change your motion in the different situations.

What a movie where the legendary physics Richard Feynman talks about a discussion with his father. He starts by telling about the observation of a ball in a little "express wagon", which seemed to roll to the back of the wagon as he pulled the wagon forwards. He asked his dad "I noticed something ... why is that?" "That", said the father, "nobody knows. The general principle is that things that are moving tend to keep on moving, and things that are still  tend to stay still unless you push on them. This tendency is called 'inertia', but no-one knows why it is true". Feynman then discusses the difference between knowing the name of something and knowing something