Forces on an Ice Cube

Learning Intentions

• To learn the difference between normal force and the force of friction
• To understand that the normal force will be as large as needed
• To understand the the friction force will depend on the coefficient of friction

Notes

1. Take an ice cube from the front of the class.
2. Try to hold the ice cube in the palm of your hand.
   1. Where is the normal force?
   2. Where is the friction force?
3. Try to hold the ice cube in a pincer grip with your thumb and index finger.
   1. Where is the normal force?
   2. Where is the friction force?
4. Why is it so easy to hold ice in the palm of your hand, but not using a pincer grip?
5. What implications does this have for walking safely on ice?