676512376-SCIENCE-8-PPT-W3Quarter 1-4.pptx

Science 8 Week 1, Quarter 1

1. SCIENCE 8 September 28, 2021 Week 3 Quarter 1

2. Prayer

3. Attendance

4. L:earning Competencies Identify and explain the factors that affect potential and kinetic energy. (MELC Week 2-3)

5. Lesson Objectives: After answering this entire activity sheet, you are expected to: define potential and kinetic energy; b. differentiate the two; c. identify and explain the factors that affect potential and kinetic energy; and d. solve problems involving KE and PE.

6. POTENTIAL AND KINETIC ENERGY

7. Choose the letter of the correct answer. Write your answers on a separate sheet of paper. 1. An object from a certain height falls freely. Which of the following happens to PE and KE when the object is half on its way down? A. loses PE and gains KE B. gains PE and loses KE C. loses both PE and KE D. gains both PE and KE

8. 2. How do you compare the PE of the moving object at the highest point compared to its KE? A. PE is greater than KE B. PE is equal to KE C. PE is lesser than KE D. KE is greater than PE 3. Which of the following quantities has the greatest influence on the amount of kinetic energy of a car while traveling on a highway? A. mass B. size C. speed D. weight

9. 4. Which of the following pair of quantities are the factors that affect kinetic energy? A. force and distance B. mass and height C. mass and speed D. time and height 7. Which of the following statements is TRUE about potential energy? A. It is dependent on the speed of an object. B. It does not depend on the mass of the object. C. It does not depend on the strength of gravity. D. It is affected by the mass and location of an object with respect to the ground.

10. Potential energy Potential energy is the  energy stored within an object , due to the object's position, arrangement or state.

11. What is potential energy? Potential energy is  energy that is stored  – or conserved - in an object or substance. This stored energy is based on the position, arrangement or state of the object or substance. You can think of it as energy that has the 'potential' to do work. When the position, arrangement or state of the object changes, the stored energy will be released.

12. What are the different types of potential energy? 1. Gravitational potential energy 2. Elastic potential energy

13. Gravitational potential energy Gravitational potential energy is energy in an object that is held in a vertical position, due to the force of gravity working to pull it down.

14. The amount of gravitational potential energy an object has depends on its height and mass. The heavier the object and the higher it is above the ground, the more gravitational potential energy it holds. Gravitational potential energy increases as weight and height increases.

15. Potential Energy Formula PEgrav = m • g • h m -  represents the mass of the object  h  - represents the height of the object   g  - represents the gravitational field strength (9.8 N/kg on Earth) - sometimes referred to as the acceleration of gravity.

16. A cart is loaded with a brick and pulled at constant speed along an inclined plane to the height of a seat-top. If the mass of the loaded cart is 3.0 kg and the height of the seat top is 0.45 meters, then what is the potential energy of the loaded cart at the height of the seat-top?

17. ANSWER PE = m*g*h m = 3 kg g = 9.8 m/s/s h = 0.45 m PE = (3 kg ) * (9.8 m/s/s) * (0.45 m) PE = 13.2 J

18. Elastic potential energy Elastic potential energy is energy stored in objects that can be stretched or compressed, such as trampolines, rubber bands and bungee cords. The more an object can stretch, the more elastic potential energy it has.

19. PE spring  = 0.5 • k • x 2 k = spring constant (J) x = amount of compression (m) (relative to equilibrium position)

20. A spring has an extension of 20 cm. Calculate the elastic potential energy stored in the spring (k = 100 N/m). 20N ( X )

21. A spring has an extension of 20 cm. Calculate the elastic potential energy stored in the spring (k = 100 N/m). PE spring  = 0.5 • k • x 2 Pe spring = 0.5 x 100N/m x (0.2m) Pe spring = 2J 2

22. Kinetic energy  is the energy of motion. An object that has motion - whether it is vertical or horizontal motion - has kinetic energy. 

23. The standard metric unit of measurement for kinetic energy is the Joule. As might be implied by the above equation, 1 Joule is equivalent to 1 kg*(m/s)^2. 1 Joule = 1 kg*(m/s)^2.

24. Forms of kinetic energy 

25.  1. vibrational -the energy due to vibrational motion 2. rotational -the energy due to rotational motion 3. translational -the energy due to motion from one location to another Forms of kinetic energy 

26. Kinetic Energy Formula KE = 0.5 • m • v 2 where  m  = mass of object v  = speed of object

27. Kinetic energy is a  scalar quantity ; it does not have a direction. Unlike  velocity ,  acceleration ,  force , and  momentum , the kinetic energy of an object is completely described by magnitude alone. 

28. EXERCISE  Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s.

29. ANSWER KE = 0.5 x m x v 2 KE= 0.5 x 625 kg x (18.3 m/s) 2 KE=0.5 x 625kg x 334.89m/s KE= 104,653 KE = 1.05 x10 5  Joules 105000

30. Identify whether the objects in the given situations possess Potential Energy or Kinetic Energy . Write your answers on a separate sheet of paper. 1. Bird flying 2. Log in a fireplace 3. Watermelon on a desk 4. Car travelling on the highway 5. Car sitting in a driveway 6. Bunch of coconut stick on a table 7. Ball bouncing on the floor 8. Child jumping on his bed 9. Child sleeping on the crib 10. Marble rolling down the ramp Kinetic Energy Potential Energy Potential Energy Kinetic Energy Potential Energy Potential Energy Kinetic Energy Kinetic Energy Potential Energy Kinetic Energy

31. Given the pictures below, answer the corresponding questions that follow. Write your answers on a separate sheet of paper. A ball bounces on the ground. At what position (A, B, C ) does the ball have the greatest potential energy? Kinetic energy? Explain your answer. Which bird on the wire has the more potential energy? Prove your answer using the formula of potential energy. PERFORMANCE TASK # 1 QUARTER 1

32. POINTS DESCRIPTION 20 Discussion is complete with no misconception 10 Discussion is incomplete with minor misconception. No discussion Rubric for Scoring Deadline of submission is on SEPTEMBER 19, 2023 NO EXTENSION