Rolling Racers – Moment of inertia

Inertia – the resistance of any physical object to any change in its position and state of motion. This includes changes to the object’s speed, direction, or state of rest.

  • Inertia is also defined as the tendency of objects to keep moving in a straight line at a constant velocity. The principle of inertia is one of the fundamental principles in classical physics that are still used to describe the motion of objects and how they are affected by the applied forces on them.

That’s engineering

  • load – a weight that needs to be lifted, moved or supported.
  • shock loading – Large but short lived forces, known as shock loading, can cause huge problems for engineers as they can break a structure that is otherwise very strong. Shock loading means the incredibly strong cables used to tow ships can break if they are suddenly pulled tight. Shock loading can also be useful; when you hammer in a nail you are applying a very quick huge force to the nail, causing the material you are hammering into to break, and allowing the nail to move forwards.

Engineering ideas

  • inertia, mass, force, tension, stretch, shock loading

Do It
Challenges for you to work on…

  • Inertia to your advantage – try this demonstration of inertia. Note “cotton” is regular sewing thread.
  • Balancing stick – You can feel the change in inertia for yourself when you do the experiment.