Why are simple machines used?

1. Why are simple machines used? 70 140 130 50 60 40 30 10 120 8 7 6 5 9 4 3 2 0 180 80 20 90 160 150 170 100 110 1 Seconds Remaining:

2. Simple machines are used to make work [moving an object a distance] easier.

3. Draw & Label the 3 types of levers 130 120 60 70 40 50 30 10 140 8 7 6 5 9 4 3 2 0 180 80 20 160 90 150 170 100 110 1 Seconds Remaining:

5. Describe mechanical advantage 60 140 130 120 40 50 30 10 70 8 7 6 5 9 4 3 2 0 180 20 90 160 80 150 170 100 110 1 Seconds Left:

6. The ratio of output force to input force for a machine. Ratio of resistance force to effort force in a machine. The advantage created by a machine that enables people to do work while using less force.

7. – Why is the pulley considered a simple machine?– What changes can be made to the pulley system to make work easier? 60 140 130 120 40 50 30 10 70 8 7 6 5 9 4 3 2 0 180 80 20 90 160 150 170 100 110 1 Seconds Left:

8. The pulley is considered a simple machine because it is designed to make work easier. Using a pulley would require less force to lift a heavy object. Adding a longer rope to the pulley could help make work easier.

9. List the 6 types of simple machines 60 140 130 120 40 50 30 10 70 8 7 6 5 9 4 3 2 0 180 20 90 160 150 170 80 100 110 1 Seconds Left

10. Lever • Pulley • Inclined plane • Screw • Wedge • Wheel & axle

11. A construction worker tries to remove a nail from a board using a hammer and a crowbar.The construction worker is not able to pull a nail out of a board using a hammer. When the worker tries using a crowbar, the nail comes out easily.–Use what you know about the relationship between work, force, and distance to explain why it was easier to use the crowbar to remove the nail. 60 140 130 120 40 50 30 10 70 8 7 6 5 9 4 3 2 0 180 80 20 90 160 150 170 100 110 1 Seconds Left:

12. The crowbar is easier because it is longer than the hammer. Because it is longer, the crowbar handle moves farther than the hammer. Because the crowbar pulls on the nail for a greater distance, it can do as much work using a smaller force.

13. The drawing below shows a student using a screwdriver to open a paint can. –To change the force to the lid of the paint can, the student can reposition her hand. How does moving her hand change the force applied to the lid? Seconds Left: 50 140 130 120 70 40 30 10 60 8 7 6 9 5 4 3 2 0 80 180 20 90 160 150 170 100 110 1

14. The student can move her hand closer or further from the end of the screwdriver to increase or decrease the force applied to the lid.

15. The drawing below shows a student using a screwdriver to open a paint can. –Describe how she could do this to apply less force to the screwdriver to remove the lid. Seconds Left: 50 140 130 120 70 40 30 10 60 8 7 6 9 5 4 3 2 0 180 20 90 160 150 170 80 100 110 1

16. To apply less force to the screwdriver to remove the lid, she needs to move her hand to the end of the screwdriver's handle.

17. The drawing below shows a student using a screwdriver to open a paint can. –Explain clearly how moving her hand allows her to change the force. Seconds Left: 50 140 130 120 70 40 30 10 60 8 7 6 9 5 4 3 2 0 180 20 90 160 150 170 100 110 1 80

18. The mechanical advantage of a lever is dependent on the distance the force is applied from the pivot. The larger the distance, the smaller the force.