1 / 12

STAAR Review

STAAR Review. Category 2-Force, Motion, & Energy Students demonstrate an understanding of force, motion, and energy and their relationships. Transformation of Energy. What forms? Heat, chemical, mechanical, & electrical Creating electricity from?

ellery
Download Presentation

STAAR Review

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. STAAR Review Category 2-Force, Motion, & Energy Students demonstrate an understanding of force, motion, and energy and their relationships.

  2. Transformation of Energy • What forms? • Heat, chemical, mechanical, & electrical • Creating electricity from? • geothermal, wind, burning of fossil fuels, hydroelectric, nuclear, etc. by changing forms • Law of Conservation of Energy? • energy is neither created nor destroyed, it changes forms 6.9C

  3. Transformation of Energy • Potential • Stored energy based on position; energy that can do work • Kinetic • Energy of motion; energy doing work On the next slide, explain where the ball has potential and kinetic energy. Also, where is kinetic energy the lowest and the highest? 6.8A

  4. Ball Bounce Height over Time Height (cm) Time (s) 6.8A

  5. Newton’s Laws • 1st – Law of Inertia • objects in motion stay in motion at a constant velocity and objects at rest stay at rest unless another forces acts on it • 2nd – Law of Acceleration • Acceleration = force applied to an object divided by its mass (a = F/m OR F = ma) • 3rd – Law of Action-Reaction • for every action force, there is an equal but opposite reaction force 8.6C

  6. Balanced vs. Unbalanced • Balanced forces result in… • Objects at rest staying at rest • Objects in motion stay in motion at a constant velocity • Unbalanced forced result in… • Resting objects caused to move • Objects in motion change their speed and/or direction 8.6A

  7. Motion Terms A push or pull on an object; has a size and direction • Force • Motion • Speed • Acceleration Movement; change in an object’s position over time Distance traveled over time; distance divided by time Change in speed over time; change in velocity divided by time to make change; + (speed up) or – (slow down) 8.6B

  8. Calculations • A car has a mass of 900 kg. It travels 600 m in the same direction for 30 s at a constant speed. What is its speed? • What is its acceleration? Speed = d/t = 600 m/30 s = 20 m/s Acceleration is a change in speed or direction; since the car is traveling at a “constant speed” & does not turn, its acceleration is zero. 8.6A; 6.8C

  9. Calculations • A rock is thrown from a bridge 15 m above the river with a 2.5 N force. It has a mass of 0.5 kg. What is the acceleration of the rock? F = ma 25 N = 0.5 kg x a a = 25 N / 0.5 kg a = 50 m/s2 REMINDER 1 N = 1 kgm/s2 8.6B

  10. Calculations • A Southwest airplane travels at a rate of 7 km/min at a height of 18,000 m above the Earth’s surface. How long will it take to travel from Dallas to San Antonio which is 315 km away? Speed = d / t 7 km/min = 315 km / t t = 315 km / 7 km/min t = 45 min 8.6A; 6.8C

  11. Calculations • It is 475 km from Dallas to San Antonio. How long will it take you to drive from Dallas to San Antonio if you average 100 km/h in a car with a mass of 950 kg? Speed = distance ÷ time 100 km/h = 475 km ÷ t t = 475 km ÷ 100 km/h t = 4.75 h 8.6A; 6.8C

  12. Reminders… • Energy is not created nor destroyed; it is only converted from one form to another; i.e., chemical  heat  mechanical  electrical • Potential energy is energy of position; kinetic energy is energy of motion • Forces affect motion, speed, & acceleration • Any questions???

More Related