G-"Forces"

Note: This activity might be best explored after students have studied forces.

Try this

Although used in everyday speech to describe changes in motion, a “g-force” is neither a measure of gravity nor a force! Instead, g-force can be thought of as the unit-less ratio between normal force on an object and its weight (FN/Fg). For example, someone who is experiencing “2 g’s” is experiencing a normal force that is twice the strength of the pull of gravity on their body, and the increased normal force is perceived as “apparent heaviness,” although there is no actual change in weight.

Investigate g-forces in all dimensions by using the g-Force Meter. Try orienting the smartphone or tablet differently, and seeing the effect on the total and individual g-force axes. Try to get the device to read - if only temporarily - a g-force of 0 in all dimension at the same time. Hint: The best place to try this is on a large, padded area such as a bed or sofa. (Be cautious of preventing your phone from colliding with hard surfaces, or bouncing off of a soft surface.)

Challenge yourself

• Describe the kind of motion that is necessary for all axes to read “0” g-force. Explain why this is the case.
• Describe the kind of motion that would be necessary for all axes to read “1” g-force. Explain why this is the case.
• For a device at rest, is it ever possible for the total g-force to be higher or lower than 1-g? Explain.