Objective 5: The student will demonstrate an understanding of motion, forces, and energy.

1. Objective 5:The student will demonstrate an understanding of motion, forces, and energy. Basic Physics

2. Motion and Forces Knows concepts of force and motion evident in everyday life.

3. Calculate speed, momentum, acceleration, work, and power in systems such as in the human body, moving toys, and machines. • Investigate and describe applications of Newton's laws such as in vehicle restraints, sports activities, geological processes, and satellite orbits. • Investigate and demonstrate [mechanical advantage and] efficiency of various machines such as levers, motors, wheels and axles, pulleys, and ramps.

4. Equations • There are many equations you need to know how to use. • You will get a formula sheet with constants. Be sure you know how to use it and are familiar with it.

5. Speed and Velocity • How fast you change your position. • Units: t’s up. • Speed & velocity: m/s or cm/s or km/hr • Distance: m or cm or km • Time: seconds (s) or hours (h)

6. Acceleration • Acceleration is the rate of change of velocity. • It occurs when an object changes its speed, its direction or both. • Units: • Acceleration: m/s/s or m/s2 • Velocity: m/s • Time: s

7. Force • Force is a push or pull that makes things move (accelerate). This is Newton’s second law and the force is the net force. • Units: • Force: Newtons (N) sometimes (n) • Mass: kg • Acceleration: m/s/s or m/s2

8. Newton’s First law of Motion • An object in motion will stay in motion and an object at rest will stay at rest unless acted upon by an external force. • A body persists in a state of uniform motion or of rest unless acted upon by an external force. • A body keeps doing what its doing unless forced to change. • AKA: the law of inertia.

9. Newton’s Second Law of Motion: • Force = mass x acceleration (this is a formula) • Force equals mass times acceleration. • net F = ma (formula sheet) • AKA: F = ma • With equal force… • a smaller mass object will accelerate at a large rate • a big mass will accelerate at a small rate. • With equal masses… • a larger force will accelerate it at a faster rate • a small force will accelerate it at a smaller rate.

10. Weight • You use Newton’s second law to calculate something’s weight. • The acceleration you would use is the acceleration due to gravity; 9.8 m/s/s This is given to you on the formula sheet. Weight = mass (in kilograms) x 9.8 m/s/s • Your weight would be in Newtons (N)

11. Newton’s Third Law of Motion: • For every action there is an equal and opposite reaction. • AKA: Action – Reaction Law • Action – Reaction Pairs. • Action: Joe hits Jack Reaction: Jack hits Joe • Action: Bob pulls on box Reaction: Box pulls on Bob • Action: Earth pulls on Moon Reaction: Moon Pulls on Earth

12. Gravity • The pull of gravity depends on the size of the objects (masses) and the distance between their centers. • This is explained by Newton’s Universal Law of Gravity. There is gravity between all objects in the universe. • Increasing the masses of one or both objects increases the force between them. • Increasing the distance between their centers, decreases the force of gravity (by a square).

13. Gravity and Circles • Objects travel in a circle because something holds it in orbit. • This force is the pull of gravity. • It is caused by the two objects in question and the distance between them. • The pull of gravity is everywhere.

14. Momentum, p • Momentum is moving mass. • Momentum is mass times its velocity. • Momentum, p, is measured in either: • kg m/s or g cm /s • There is a formula for momentum.

15. Momentum • Momentum is a concept of moving mass. • Units: • Momentum: kg m/s or g cm/s • Mass: kilograms (kg) or grams (g) • Velocity: m/s or cm/s

16. Conservation of Momentum • The total momentum before equals the total momentum after. • In dealing with momentum, directions matter.

17. Conservation of Momentum • The total momentum before a happening or collision equals the total momentum after. • You find themvof each object before a collision and the mvof each object after and they must be equal. • Momentum is a vector so its direction matters. The direction of the momentum is the same direction as its velocity. • They like momentum problems.

18. Energy Knows the impact of energy transformations in everyday life.

19. Describe the law of conservation of energy. • Investigate and demonstrate the movement of heat through solids, liquids, and gases by convection, conduction, and radiation. • Investigate and compare economic and environmental impacts of using various energy sources such as rechargeable or disposable batteries and solar cells.

20. Convection • A form of heat transfer through liquids and gases (fluids). • Heat is transferred by currents in the fluids. • Heat moved by fluid motion.

21. Conduction • Heat transferred by vibrating neighboring molecules. • Heat transferred through solids. • Heat moves from hot to cold.

22. Radiation • Heat transferred by waves. • Heat from our Sun reaches us through waves.

24. Work, W • Work is defined as force acting over a distance. • The force must move the object. • There is a formula for work. • Work, W , is measured in Joules, J.

25. Work • Work is force acting over a distance. The force must move the object. • Units: • Work Joules (J) sometimes (j) • Force: N • Distance: m

26. Kinetic Energy • Energy of motion. • If an object is moving it has kinetic energy. • There is a formula for kinetic energy. • Energy is measured in Joules, J.

27. Kinetic Energy • Energy due to motion. • Units: • KE: Joules (J) • Mass: kg • Velocity: m/s

28. Potential Energy • Potential energy is stored energy. • For TAKS, It is energy due to an object’s height. • There is a formula for potential energy. • Energy is measured in Joules, J. • Changes in potential energies are important.

29. Gravitational Potential Energy • Energy due to its position and the pull of gravity. • Units: • PE: Joules (J) • Mass: kg • Acceleration due to gravity: 9.8 m/s/s • Height: m

30. Conservation of Energy • The total energy before equals the total energy after. • Energy can change forms. • Work is a form of energy.

31. Conservation of Energy • Energy must be accounted for. • Energy can change forms from Potential Energy to Kinetic Energy and back again. The total amount of energy a system can have can change by doing work in the system. • The total energy of a system equals a constant. • Energy can be lost to: Work done by friction and lost to heat. • KE + PE at one place = KE + PE at another place

33. Power; Mechanical • Power is how fast work is done or how fast energy is generated or used up (dissipated). • Units: t’s up. • Power: Watts (W) or kiloWatts kW • Work: J • Time: s

34. Machines • A machine is a device that takes work (force x distance) and increases the applied force by decreasing the distance. It’s a trade off. You always need more input work than you get out because some work goes to overcome friction and heat. • There is no such thing as a 100% efficient machine. • You never get out more than you put in. • Simple machines • Lever • Pulley • Screw • Inclined plane • Wedge • Wheel and Axle

35. Which lever would require the least effort to lift the box ? A C B D

36. Levers load distance distance force fulcrum or pivot If in balance: load x distance = distance x force

37. Efficiency: Machines • A percentage of how much work you do goes into doing the job. • Units: • Efficiency is a %, no units • Work: J

38. The 6 Simple Machines

39. Energy - Mass • This is the connection between mass and energy. Einstein’s equation. • Units: • Energy: Joules (J) • Mass: kg • c = 3 x 108 m/s

40. Waves Knows the effects of waves on everyday life.

41. Demonstrate wave interactions including interference, polarization, reflection, refraction, and resonance within various materials.

42. Wave • A wave is a disturbance (energy) carried through a material medium. (mechanical wave) • Light is an electromagnetic wave. It does not need a material medium to travel through. • There are two types of mechanical waves: • Transverse waves are made perpendicular to the medium. • Longitudinal waves are made parallel to the medium.

43. Wave Equation • This is the equation you use with waves. • Units: • Velocity: m/s • Frequency: Hertz (Hz) • Wavelength: m

44. Wave Parts

45. Frequency, f • Frequency, f , is how many things happen in one second. • How many waves are made in 1 second. • Frequency , f , is measured in Hertz, Hz.

46. Period, T • The amount of time it takes to do something once. • The amount of time to make one wave. • Period, T , is measured in seconds, s.

47. Wavelength, λ • The length of one wave is called the wavelength. • It’s the distance from crest to crest, trough to trough, or from corresponding part to like corresponding part. • Wavelength, λ , is .measured in meters, m

48. Amplitude • The height of a wave from equilibrium, or the depth of the wave from equilibrium. • Amplitude is usually measured in meters, m.

49. Medium • The stuff that carries the wave. • Sound travels in air. • Water waves travel in water. • Earth quakes travel in dirt (earth) • Light travels in empty space (light is an electromagnetic wave and does not need a medium)

50. Wave Properties