The Disc Brakes of a High Performance Car Are Often

question 11

Multiple Choice

The disc brakes of a high performance car are often made of carbon fiber instead of iron,thereby reducing the mass.If both types of discs are of the same size and shape,and each iron disc has a mass of 4 kg and each carbon disc has a mass of 1 kg,what is the reduction in rotational kinetic energy at 72 km/h if all the four iron discs in the car are replaced with carbon discs?

• A)300 J
• B)400 J
• C)800 J
• D)1200 J
• E)1600 J

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Definitions:

Pygmalion Effect

The phenomenon whereby higher expectations lead to an increase in performance; a form of self-fulfilling prophecy in the context of personal or organizational development.

Expectations

Beliefs or anticipations about the way things will or should be, often shaping behavior and perceptions.

Performance

A measurement of how effectively a task or activity is being accomplished.

Self-Fulfilling Prophecy

A psychological phenomenon where a belief or expectation, whether correct or not, influences behavior in a way that causes the belief to become a reality.