Simple Machines — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. Which simple machine is a ramp an example of?
A) Lever
B) Wedge
C) Inclined plane
D) Pulley
A ramp is an inclined plane — a flat, sloped surface that makes it easier to move objects up or down.
2. How does a pulley make work easier?
A) It increases the weight of the load
B) It changes the direction of the force
C) It removes all friction
D) It makes objects lighter
A pulley changes the direction of the force — when you pull down on the rope, the load goes up.
3. A screw is best described as which of the following?
A) A flat surface used to slide objects
B) A bar that turns on a fulcrum
C) An inclined plane wrapped around a rod
D) A thin blade that splits things apart
A screw is an inclined plane wrapped in a spiral around a central rod, which helps it push into or hold materials together.
4. Which pair of objects are both examples of a wedge?
A) Doorknob and steering wheel
B) Knife and axe
C) Seesaw and crowbar
D) Flagpole rope and blinds cord
A knife and an axe are both wedges because they use a thin, sharp edge to cut or split materials apart.
Part B: Fill in the Blank
Write the correct answer on each line.
1. A lever needs a fulcrum to work as a turning point.
The fulcrum is the fixed support point on which a lever balances and rotates.
2. A wheelbarrow combines a lever and a wheel and axle.
The axle is the rod at the center of a wheel, and together they reduce friction and make it easier to move or turn objects.
3. Simple machines make work easier by reducing the force you must apply.
Simple machines make work easier by reducing the amount of force required, though you may need to apply that force over a greater distance.
4. A zipper uses tiny wedges that lock and unlock as you pull the tab.
Wedges are simple machines with thin, sharp edges used to split, cut, or separate materials.
5. Moving a piano up a long ramp requires less force but more distance.
Using a longer ramp means you travel a greater distance, but the force needed to move the load is reduced.