Unit 1, Motion, Science Review

1. Unit 1, Motion, Science Review

2. Newton’s 1st and 2nd Laws of Motion

3. Newton’s 3rd Law of Motion

4. Kinetic and Potential Energy

5. Other Types of Energy

6. Energy Transformation • A toaster transforms electrical energy into heat to toast bread, your body transforms chemical energy from food to mechanical energy to move your arms. • If you were to juggle oranges, the orange at the highest point would have potential energy, and as gravity pulls it down, kinetic energy increases. • Look at the energy transformation of a pendulum:

7. Law of Conservation of Energy When one form of energy is transformed to another, no energy is destroyed in the process. The total amount of energy is the same before and after the transformation.

8. Graphing Motion You can show the motion of an object on a line graph in which you plot distance v. time. Look at the following graphs. The first one shows a constant speed. The second shows acceleration, then no change in distance, then an increase of speed from 150m/min. at the beginning, to 200m/min. near the end.

9. Speed, Velocity and Acceleration

10. Simple Machines 6 Types Lever Rigid bar free to pivot or rotate on a fixed point (fulcrum). Think of a see-saw. Where would you put the fulcrum to move the heavy rock easily? • Levers • Screws • Wheel & Axel • Inclined Plane • Wedge • Pulleys fulcrum

11. Simple Machines –inclined planes and wedges Inclined Plane Wedge Thick at one end and tapered at the other Some examples of wedges are: a zipper, a knife, or an ax. Instead of moving objects along an inclined plane, you move the wedge. • An inclined plane is a flat, sloped surface. It can make moving heavy objects easier. • It allows you to exert your input force over a longer distance. The input force needed is less than the output force. The output force is the force that you would need to lift the object without the inclined plane.

12. Simple Machines – screws, wheel & axle Screw Wheel and Axle Made of two circular or cylindrical objects fastened together that rotate about a common axis. • Inclined Plane wrapped around a cylinder. The spiral inclined plane forms the thread of the screw. Screws are used to fasten wood, and are also found on jar lids. • As the threads of a screw turn, they exert an output force on the wood, pulling the screw into the wood. Friction between the screw and the wood holds the screw in place.

13. Simple Machines Wheel & Axle, Pulley Wheel & Axle Pulley Made of two circular objects fastened together that rotates about a common axis. A car’s steering wheel is another example of a wheel and axle. • Made of a grooved wheel with a rope or cable wrapped around it. You use a pulley by pulling on one end of the rope, the output force pulls up on the object yu want to move. It makes work easier by decreasing the amount of input force needed, and by changing the direction of your input force, for example, you pull down on the flagpole rope, and the flag moves up. • There are fixed and moveable pulleys.

14. Pulleys Continued

15. Think about it: If you need to push a box up an inclined plane coated with different surfaces where one section of the plane is sand paper, another is ice, and another is metal with tiny holes; which surface of the three would make the job easier for you? What else would make the job easier for you? Why doesn’t the paper wad some of you throw behind my back, continue sailing on and on in the same position?

16. Think about it (more): Why doesn’t the paper wad some of you throw behind my back, continue sailing on and on in the same position? If you have something on Earth that is too heavy to lift without a machine, why would you be able to lift it in outer space?