Simple Machines — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
Scissors are an example of a wheel and axle.
Corrected: Scissors are an example of two levers.
The corrected sentence is: "Scissors are an example of two levers.". The original sentence "Scissors are an example of a wheel and axle." contained an error that needed to be fixed.
2. Fix the sentence:
An axe is a type of pulley used to split wood.
Corrected: An axe is a type of wedge used to split wood.
The corrected sentence is: "An axe is a type of wedge used to split wood.". The original sentence "An axe is a type of pulley used to split wood." contained an error that needed to be fixed.
3. Fix the sentence:
A flagpole uses a lever to raise the flag.
Corrected: A flagpole uses a pulley to raise the flag.
The corrected sentence is: "A flagpole uses a pulley to raise the flag.". The original sentence "A flagpole uses a lever to raise the flag." contained an error that needed to be fixed.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. A plane is a flat surface that is higher on one end, like a ramp.
A ramp is an inclined plane, which is a flat sloping surface that makes it easier to move objects up or down.
2. A wheel and axle work together to make turning easier.
A wheel and axle is a simple machine where a wheel is attached to a rod (axle) to reduce friction and make turning easier.
3. A wedge has a thin edge that is used to push things apart.
A wedge has a thin edge that pushes objects apart, making it easier to split or separate materials.
4. Simple machines help people do work using less effort.
The effort force is the push or pull a person applies to a simple machine to move a load.
Part C: True or False?
Read each statement. Circle True or False.
1. A wheel and axle help reduce friction when moving objects.
True False
The statement is true based on simple machines concepts.
2. A wedge is thick on both ends and thin in the middle.
True False
The statement is false; check the simple machines concept carefully.
3. A pulley changes the direction of the force you apply.
True False
The statement is true based on simple machines concepts.