Which simple machine consists of two wheels connected to rotate together?

• A. Pulley
• B. Wheel and Axle
• C. Lever
• D. Inclined Plane

Answer: (B)

Two wheels sharing the same axis describe a wheel and axle. In this setup, the wheel and the axle are fixed together so they rotate as one piece. When you turn the larger wheel, the smaller axle turns with it, transferring torque along the common axis. The advantage comes from the size difference: the input force applied at the wheel rim is multiplied (or divided) by the ratio of the wheel’s radius to the axle’s radius, allowing you to move a load with more or less effort depending on the radii.

This matches the description of two wheels connected to rotate together because they are physically attached to the same axis and turn in unison. Other options involve different configurations—pulleys involve belts or ropes and do not require fixed rotation as a single unit, while levers and inclined planes rely on different geometries and pivot points.