The disc brake of a high performance car is often made of carbon fiber instead of iron, thereby reducing the mass. If the mass of a carbon disc is that of iron for the same shape and size, by what factor is the moment of inertia changed?
A) one quarter
B) half
C) unchanged
D) doubled
E) quadrupled

Question

Quizplus · Accepted Answer

The moment of inertia is proportional to the mass. If the mass is reduced by a factor of 4, the moment of inertia will also be reduced by a factor of 4.

The Disc Brake of a High Performance Car Is Often