Simple Machines

How do levers, pulleys, wheels, and ramps make work easier?

An exploration of how six classic simple machines use mechanical advantage to make difficult tasks easier by trading force for distance.

Check your understanding

1. Which simple machine uses a stiff bar and a fulcrum to help lift heavy objects?
- A. Pulley
- B. Lever
- C. Screw
- D. Wedge
2. What happens to the total amount of work when you use a simple machine?
- A. It increases
- B. It disappears
- C. It stays the same
- D. It becomes zero
3. Which tool is essentially a flat, slanted surface used to move objects up or down?
- A. Inclined plane
- B. Wheel and axle
- C. Screw
- D. Pulley
4. A screw is most similar to which other type of simple machine?
- A. Lever
- B. Pulley
- C. Inclined plane
- D. Wheel

1. Why does pushing a box up a long ramp feel easier than lifting it straight up?
- A. The ramp creates more friction
- B. The work is spread over a longer distance
- C. The ramp changes the weight of the box
- D. The ramp adds energy to the box
2. If you use a pulley to pull down on a rope to lift a flag, what is the machine doing?
- A. Reducing the weight of the flag
- B. Adding power to the rope
- C. Changing the direction of your force
- D. Eliminating the need for work
3. Which of these is a common misconception about simple machines?
- A. They help us work smarter
- B. They require electricity to function
- C. They help us move heavy objects
- D. They trade force for distance
4. A doorknob is a great example of a wheel and axle. How does it make work easier?
- A. It acts like a ramp
- B. It splits the wood
- C. It turns a small force into a larger turning force
- D. It reduces the total work needed to open the door

Watch the lesson, take the quiz, and ask a safe AI tutor anything about it.