What is the main functional difference between a brake and a clutch in a drive system?

• A. A brake transmits torque; a clutch stores energy
• B. A brake stops or slows motion
• C. A brake stops or slows motion; a clutch engages or disengages power transmission
• D. A brake changes gear ratio; a clutch changes direction

Answer: (C)

The essential difference is how each device interacts with motion in a drive system. A brake slows or stops moving parts by applying friction, converting kinetic energy into heat, and it doesn’t pass torque to another component. A clutch, on the other hand, decides whether power is transmitted from the input to the output: when engaged, torque flows and motion is driven; when disengaged, the drive is disconnected and motion on the driven side can cease or change independently.

That’s why the correct description is that a brake stops or slows motion, while a clutch engages or disengages power transmission. The other ideas mix up these roles—brakes don’t transmit torque, a clutch doesn’t store energy, and gear changes or direction aren’t the primary functions described here.