Grade 9 Science practice

What is on the worksheet

1. A constant current of 5 A flows for 30 s. How much charge passes in C?

2. A hypothetical element has isotopes of mass 58 u (40%) and 63 u (60%). Calculate its mean atomic mass in u.

3. A steady DC device operates at 31 V and 7 A. Find power in W.

4. A repeating signal has frequency 186 Hz. Find its period in seconds as a fraction.

5. A hypothetical element has isotopes of mass 33 u (65%) and 37 u (35%). Calculate its mean atomic mass in u.

6. A steady DC device operates at 43 V and 15 A. Find power in W.

7. A device receives 4600 J and delivers 920 J of useful energy. Find its efficiency as a percentage.

8. A 28 kg object has speed 7 m/s. Find its classical kinetic energy in J.

9. A sample has mass 396 g and volume 22 cm³. Calculate density in g/cm³.

10. A constant 100 N force acts in the same direction as a 29 m displacement. Find work in J.

11. A periodic wave has frequency 62 Hz and wavelength 18 m. Find its speed in m/s.

12. A perpendicular force of 1824 N acts over 24 m². Find the pressure in Pa.

13. A model vehicle travels 1200 m in 15 s at constant speed. What is its speed in m/s?

14. A device transfers 55 J in 5 s. Find average power in W.

15. In a simplified isotope exercise, atomic number Z = 11 and mass number A = 38. How many neutrons?

16. A steady DC device operates at 18 V and 15 A. Find power in W.

17. A hypothetical element has isotopes of mass 73 u (25%) and 78 u (75%). Calculate its mean atomic mass in u.

18. In a simplified isotope exercise, atomic number Z = 11 and mass number A = 33. How many neutrons?

19. A model vehicle travels 1836 m in 36 s at constant speed. What is its speed in m/s?

20. A 50 kg object has speed 5 m/s. Find its classical kinetic energy in J.