1. Derive the formula for potential energy. 2. Explain the Law of conservation of energy with pendulum. 3. If energy is neither created nor destroyed then from where do we get energy? 4. State and explain one example where kinetic energy is present in a body and is used. 5. Define power and give its unit. 6. What is potential energy? Explain different types of potential energy. 7. How is work and energy related to each other? 8. Give one example where work done on an object is negative. 9. A man does 60 J of work in 6 seconds. Calculate the power. 10. Give one example where work done on an object is zero.
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Explanation:
That's a lot of questions!
1. **Deriving the formula for potential energy:** Potential energy is typically derived based on the force exerted on an object and its position within a force field. For example, gravitational potential energy (\(PE_{\text{gravity}}\)) near the Earth's surface can be derived as \(PE_{\text{gravity}} = mgh\), where \(m\) is the mass, \(g\) is the acceleration due to gravity, and \(h\) is the height.
2. **Law of conservation of energy with a pendulum:** The law states that energy cannot be created or destroyed, only transformed from one form to another. In a pendulum, potential energy is highest at the highest point, converting to kinetic energy at the lowest point, and the sum of these energies remains constant disregarding any losses due to friction or air resistance.
3. **Source of energy:** Energy is not created or destroyed, but rather transformed from one form to another. The primary sources of energy are often natural resources like the sun (solar energy), fossil fuels, wind, water, and nuclear reactions.
4. **Example of kinetic energy being used:** When a car moves, its kinetic energy is in action. The energy from the car's movement is utilized to power its various systems, including the engine, lights, and sound systems.
5. **Definition of power and its unit:** Power is the rate at which work is done or the rate at which energy is transferred or converted. Its unit is the watt (W), and it's defined as one joule per second.
6. **Potential energy:** Potential energy is stored energy based on an object's position or condition. Types include gravitational potential energy, elastic potential energy (like in a stretched spring), chemical potential energy (stored in chemical bonds), and more.
7. **Relationship between work and energy:** Work is the transfer of energy. When work is done on an object, energy is transferred to or from the object, causing a change in its state or motion.
8. **Example of negative work:** If you apply force opposite to an object's displacement, the work done is negative. For instance, if you push a box backward while it moves forward due to another force, the work done by your force is negative.
9. **Calculating power:** Power is the rate of doing work. So, if a man does 60 J of work in 6 seconds, his power can be calculated as Power = Work / Time.
10. **Example of zero work:** When you hold a book still in your hand, even though you're exerting force, the book doesn't move, and thus, no work is done.