Questions: Wheel and Axle

Question 1

Why is a doorknob easier to turn than the thin rod inside the door?

• A. The doorknob is slippery
• B. The doorknob is a larger wheel that multiplies your force on the smaller axle
• C. The doorknob weighs less
• D. The rod is stuck

Answer: (B)

The doorknob acts as the wheel. Because it is larger than the rod (axle), a small turning force on the knob becomes a bigger turning force on the rod.

Question 2

A wheel and axle is a simple machine.

• T. True
• F. False

Answer: True

A wheel and axle is one of the six classic simple machines. It uses a larger wheel connected to a smaller axle to multiply force or speed.

Question 3

Name one example of a wheel and axle that is NOT on a vehicle.

Model answer: A doorknob (also acceptable: screwdriver, faucet handle, steering wheel, fishing reel, pencil sharpener).

Many everyday objects use the wheel-and-axle principle — any time a larger knob or handle turns a thinner rod, that is a wheel and axle.