brodidit for students
کام اور توانائی
نویں جماعت · طبیعیات · 10 سوالات
نام: ____________________ تاریخ: ____________
What is the SI unit of work?
- A Joule
- B Newton
- C Pascal
- D Watt
How much work is done by a force of 20 N moving a body 5 m in its own direction?
- A 15 J
- B 25 J
- C 100 J
- D 4 J
What is the kinetic energy of a 2 kg body moving at 3 m/s?
- A 6 J
- B 12 J
- C 9 J
- D 18 J
What is the potential energy of a 5 kg mass at a height of 10 m? (g = 10 m/s²)
- A 15 J
- B 50 J
- C 500 J
- D 5 J
Power is defined as:
- A Energy x distance
- B Force x time
- C Work x time
- D Work / time
A machine does 600 J of work in 20 s. What is its power?
- A 3 W
- B 580 W
- C 30 W
- D 12000 W
Energy cannot be created or destroyed, only changed from one form to another. This is the law of:
- A Gravitation
- B Reflection
- C Conservation of energy
- D Inertia
A falling stone's potential energy changes mainly into:
- A Sound only
- B Light
- C Nuclear energy
- D Kinetic energy
1 kilowatt hour equals:
- A 3600 J
- B 3.6 x 10⁶ J
- C 3.6 x 10³ J
- D 1000 J
Which of these is a renewable source of energy?
- A Solar
- B Petrol
- C Natural gas
- D Coal
جوابی کلید
1. A, 2. C, 3. C, 4. C, 5. D, 6. C, 7. C, 8. D, 9. B, 10. A
Work is measured in joules.
W = F x d = 20 x 5 = 100 J.
KE = 1/2 m v² = 0.5 x 2 x 9 = 9 J.
PE = m g h = 5 x 10 x 10 = 500 J.
Power is the rate of doing work: P = W / t.
P = W / t = 600 / 20 = 30 W.
This is the law of conservation of energy.
As it falls it speeds up.
1 kWh = 1000 W x 3600 s = 3.6 x 10⁶ J.
Solar energy is renewable.