# Pulleys. Pulleys can: Change the direction of the effort force. Reduce the effort force needed. –M.A. > 1 – The larger the M.A. the longer the distance.

## Presentation on theme: "Pulleys. Pulleys can: Change the direction of the effort force. Reduce the effort force needed. –M.A. > 1 – The larger the M.A. the longer the distance."— Presentation transcript:

1 Pulleys

2 Pulleys can: Change the direction of the effort force. Reduce the effort force needed. –M.A. > 1 – The larger the M.A. the longer the distance over which the work must be done.

3 Single Fixed Pulley M.A = 1 Advantage: direction of the effort force changed.

4 Single Movable Pulley M.A. = 2 Advantage: reduces effort force needed.

5 1 Movable & 1 Fixed Pulley Advantage: reduces effort force and changes direction.

6 2 Movable & 1 Fixed Pulley M.A. = 4 Combination of several pulleys working together =compound pulley system Combination of fixed and moveable pulleys =block and tackle system

7 Determining Mechanical Advantage When counting the number of strands to determine M.A., only count the strands holding the load up. –If you are pulling up on the load you count it as a strand, but if you are pulling down you don’t count it.

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