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Grade 8 · Physics

Grade 8 Energy, work & power worksheet

20 questions on energy, work & power. The answer key is a separate download.

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What is on the worksheet

  1. A device receives 1330 J and has useful-energy efficiency 55%. Find the useful output energy. Round to 3 decimal places if needed. Answer in J.

  2. A 28 kg load is raised vertically by 27 m in a field g = 10 N/kg. Find its gravitational potential-energy gain. Round to 3 decimal places if needed. Answer in J.

  3. A model device transfers energy at constant power 30 W for 75 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  4. A model device transfers energy at constant power 480 W for 24 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  5. A 20 kg load is raised vertically by 7 m in a field g = 10 N/kg. Find its gravitational potential-energy gain. Round to 3 decimal places if needed. Answer in J.

  6. A model device transfers energy at constant power 480 W for 76 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  7. A 15 kg load is raised vertically by 19 m in a field g = 10 N/kg. Find its gravitational potential-energy gain. Round to 3 decimal places if needed. Answer in J.

  8. A model device transfers energy at constant power 400 W for 33 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  9. A 34 kg load is raised vertically by 26 m in a field g = 10 N/kg. Find its gravitational potential-energy gain. Round to 3 decimal places if needed. Answer in J.

  10. A model device transfers energy at constant power 305 W for 74 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  11. A 26 kg load is raised vertically by 4 m in a field g = 10 N/kg. Find its gravitational potential-energy gain. Round to 3 decimal places if needed. Answer in J.

  12. A model device transfers energy at constant power 870 W for 61 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  13. A model device transfers energy at constant power 945 W for 45 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  14. A model device transfers energy at constant power 810 W for 46 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  15. A 24 kg load is raised vertically by 16 m in a field g = 10 N/kg. Find its gravitational potential-energy gain. Round to 3 decimal places if needed. Answer in J.

  16. A device receives 290 J and has useful-energy efficiency 95%. Find the useful output energy. Round to 3 decimal places if needed. Answer in J.

  17. A model device transfers energy at constant power 490 W for 26 s. Find the transferred energy. Round to 3 decimal places if needed. Answer in J.

  18. A 29 kg load is raised vertically by 17 m in a field g = 10 N/kg. Find its gravitational potential-energy gain. Round to 3 decimal places if needed. Answer in J.

  19. A device receives 540 J and has useful-energy efficiency 65%. Find the useful output energy. Round to 3 decimal places if needed. Answer in J.

  20. A device receives 1270 J and has useful-energy efficiency 30%. Find the useful output energy. Round to 3 decimal places if needed. Answer in J.

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