Physics: Simple Machines Pulleys Wheels and Gears Worksheet

Question 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?

Accepted Answer

The simple machine is a fixed pulley. It helps by changing the direction of the force, so pulling down on the rope lifts the flag up.

Question 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?

Accepted Answer

A movable pulley reduces the force needed to lift the box, but the worker must pull the rope a longer distance.

Question 3

Circle the object that is an example of a wheel and axle: spoon, doorknob, book, or pencil eraser. Explain your choice.

Accepted Answer

The doorknob is an example of a wheel and axle because the larger knob turns a smaller axle inside the door.

Question 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.

Accepted Answer

The larger gear turns more slowly because it has twice as many teeth as the smaller gear. The small gear must turn two times to make the large gear turn once.

Question 5

Two gears are touching. Gear A turns clockwise. Which direction will Gear B turn?

Accepted Answer

Gear B will turn counterclockwise because touching gears turn in opposite directions.

Question 6

A student says, "A fixed pulley makes a load lighter." Is the student correct? Explain your answer.

Accepted Answer

The student is not correct. A fixed pulley mostly changes the direction of the force, but it does not greatly reduce the force needed to lift the load.

Question 7

A cart has large wheels. Explain how wheels help the cart move more easily across the floor.

Accepted Answer

Wheels help the cart move more easily by reducing friction. Instead of the cart sliding across the floor, the wheels roll.

Question 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?

Accepted Answer

About 20 pounds of pulling force is needed because the 40-pound weight is shared by 2 rope sections.

Question 9

Name one everyday machine that uses gears, and explain what the gears do in that machine.

Accepted Answer

A bicycle uses gears. The gears help change how fast the wheels turn and how hard the rider must pedal.

Question 10

A screwdriver has a thick handle and a thin metal shaft. Explain how this tool acts like a wheel and axle.

Accepted Answer

The thick handle acts like the wheel, and the thin shaft acts like the axle. Turning the larger handle helps twist the smaller shaft with more turning force.

Question 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?

Accepted Answer

Gear C will turn clockwise. Gear B turns counterclockwise because it touches Gear A, and Gear C turns clockwise because it touches Gear B.

Question 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?

Accepted Answer

The tradeoff is that the person uses less force but pulls the rope a longer distance. Simple machines can make force easier while increasing the distance moved.

Question 13

Look at a bicycle wheel. Identify the wheel and the axle in this system.

Accepted Answer

The tire and rim are the wheel, and the rod through the center is the axle. The wheel turns around the axle as the bicycle moves.

Question 14

A crane uses pulleys to lift building materials. Give two reasons pulleys are useful in cranes.

Accepted Answer

Pulleys are useful in cranes because they can change the direction of the pulling force and can reduce the force needed when several rope sections support the load.

Question 15

Sort each item into the correct simple machine group: flagpole pulley, skateboard wheel, clock gears, fishing reel handle, elevator pulley, bicycle gears.

Accepted Answer

Flagpole pulley and elevator pulley belong in the pulley group. Skateboard wheel and fishing reel handle belong in the wheel and axle group. Clock gears and bicycle gears belong in the gear group.

Physics: Simple Machines Pulleys Wheels and Gears

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