Gear transmit _______ between machines while changing rotation, speed, and torque.

Gear transmit _______ between machines while changing rotation, speed, and torque.

• A. Power
• B. Force
• C. Energy
• D. Momentum

Answer: (A)

Power is transmitted between machines by gears. Gears connect two shafts and, through gear ratios, change rotation speed and torque. The quantity that actually moves from one machine to the other is power—the rate at which work is done. In an ideal gear system, power in equals power out (minus losses), and since power equals torque times angular velocity, changing the gear ratio increases speed on one side while decreasing torque on that side, so the product stays the same. This is why gears can speed up or slow down rotation while changing torque, yet effectively transfer the same amount of mechanical power. Energy describes the total work transferred, not the rate, and force is the instantaneous contact force between teeth, while momentum isn’t the quantity used to describe this transmission.

Power is transmitted between machines by gears. Gears connect two shafts and, through gear ratios, change rotation speed and torque. The quantity that actually moves from one machine to the other is power—the rate at which work is done. In an ideal gear system, power in equals power out (minus losses), and since power equals torque times angular velocity, changing the gear ratio increases speed on one side while decreasing torque on that side, so the product stays the same. This is why gears can speed up or slow down rotation while changing torque, yet effectively transfer the same amount of mechanical power. Energy describes the total work transferred, not the rate, and force is the instantaneous contact force between teeth, while momentum isn’t the quantity used to describe this transmission.