• Inclined PlaneA common inclined plane is a ramp. Lifting a heavy box onto a loading dock is much easier if you slide the box up a ramp--a simple machine.

• Wedge

Instead of using the smooth side of the inclined plane, you can also use the pointed edges to do other kinds of work. For example, you can use the edge to push things apart. Then, the inclined plane is a wedge. So, a wedge is actually a kind of inclined plane. An axe blade is a wedge.

• ScrewTake an inclined plane and wrap it around a cylinder. Its sharp edge becomes another simple tool: the screw. Put a metal screw beside a ramp and it's kind of hard to see the similarities, but the screw is another kind of inclined plane.

Lever Any tool that pries something loose is a lever. A

lever is an arm that "pivots" (or turns) against a "fulcrum" (or point). Think of the claw end of a hammer that you use to pry nails loose. It's a lever.

Wheel and AxleAnother kind of lever, the wheel and axle, moves objects across distances. The wheel, the round end, turns the axle, the cylindrical post, causing movement.

PulleyInstead of an axle, the wheel could also rotate a rope or cord. This variation of the wheel and axle is the pulley. In a pulley, a cord wraps around a wheel. As the wheel rotates, the cord moves in either direction. Now, attach a hook to the cord, and you can use the wheel's rotation to raise and lower objects.

Inclined Plane

5 N5 N

applyforce

applyforce

Inclined Plane

Decreases the size of the effort force

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Inclined Plane

The size of the effort force on the incline is still less than the vertical lift.

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5 N

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Inclined Plane

Basically, an incline plane allows you to decrease the effort force applied by increasing the distance of the effort force.

3 N

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Life, Force, and Motion

• Every time you move something, use your pencil, or walk, you are using force.

• Developing and growing plants use force to grow, reproduce, and survive.

• These forces are examples of everyday life because that is what a force is, everyday life.

Mechanical Advantage• Mechanical

advantage of an inclined plane is the length of the slope divided by the height of the plane, if effort is applied parallel to the slope

• So for our plane MA = 15

feet/3 feet = 5

• Let’s say S = 15 feet, H = 3 feet

Inclined Plane• The mechanical

advantage of an inclined plane is equal to the length of the slope divided by the height of the inclined plane.

• While the inclined plane produces a mechanical advantage, it does so by increasing the distance through which the force must move.

Tropisms

• A tropism is a growth response involving bending or curving of a plant part toward or away from an external stimulus that determines the direction of movement

• Response toward the stimulus is positive, and response away from the stimulus is negative

• An unbalanced force is needed to carry out this biological process.

Phototropism• Phototropism is the growth of stems of

plants toward light - it is probably the best known of the plant tropisms

• phototropism is caused by elongation of the cells on the shaded part of the plant - so that entire plant bends or curves toward the light

Phototropism in plants

Light source

Phototropism: differential stem growth

Greater force applied

Gravitropism

Gravitropism is a response to gravity - if a seedling is placed on its side, the root will curve to grow downward and the shoot will curve to grow upward

Root Growth

• The main root of a plant typically grows downwards towards earths gravity.

• This downwards oriented growth is termed gravitropism.