Practice explaining how pulleys, wheels and axles, and gears make work easier in everyday machines.
Read each problem carefully. Write your answer in complete sentences when asked. Show your work for number problems.
How simple machines help us change force, direction, and motion
Physics - Grade 4-5
- 1
A flag is raised using a rope that goes over a wheel at the top of a flagpole. What simple machine is being used, and how does it help?
- 2
A worker uses a movable pulley to lift a heavy box. Compared with lifting the box straight up by hand, what changes about the force needed and the distance the rope must be pulled?
- 3
Circle the object that is an example of a wheel and axle: spoon, doorknob, book, or pencil eraser. Explain your choice.
- 4
A small gear with 8 teeth turns a larger gear with 16 teeth. If the small gear turns the large gear, which gear turns more slowly? Explain why.
- 5
Two gears are touching. Gear A turns clockwise. Which direction will Gear B turn?
- 6
A student says, "A fixed pulley makes a load lighter." Is the student correct? Explain your answer.
- 7
A cart has large wheels. Explain how wheels help the cart move more easily across the floor.
- 8
A bucket weighs 40 pounds. A pulley system has 2 rope sections supporting the bucket. Ignoring friction, about how much pulling force is needed to lift the bucket?
- 9
Name one everyday machine that uses gears, and explain what the gears do in that machine.
- 10
A screwdriver has a thick handle and a thin metal shaft. Explain how this tool acts like a wheel and axle.
- 11
Three gears are touching in a row: Gear A touches Gear B, and Gear B touches Gear C. Gear A turns clockwise. What direction will Gear C turn?
- 12
A person pulls 6 meters of rope through a pulley system to lift a box 3 meters. What is the tradeoff shown by this simple machine?
- 13
Look at a bicycle wheel. Identify the wheel and the axle in this system.
- 14
A crane uses pulleys to lift building materials. Give two reasons pulleys are useful in cranes.
- 15
Sort each item into the correct simple machine group: flagpole pulley, skateboard wheel, clock gears, fishing reel handle, elevator pulley, bicycle gears.