Physics, Energy
Romar M. Cabinta
EXERCISES 15
WORK, ENERGY, AND POWER
A. CONCEPTUAL QUESTIONS
1. Is work done when you move a book from the top of the desk to the floor? Why?
Yes. It is because the displacement of the book from the top of the desk to the floor and the force that is applied to the book is parallel with one another.
2. State the law of Conservation of Mechanical Energy in two ways?
The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant.
TMEinitial=TMEfinal
3. Explain the basic ideas that govern the design and operation of a roller coaster.
A roller coaster is operated and designed through the application of Physics. The law of Conservation of Energy governs the changes in a coaster 's speed and height. Simply put, the higher an object is off the ground, the more potential energy it has - that is, potential to gain speed as it falls. As it falls toward the ground, that potential energy changes to kinetic energy, or energy of motion. The sum of the two types of energy is constant, but a roller coaster must maintain an adequate balance of potential and kinetic energies to deliver a thrilling ride.
4. An inefficient machine is said to “waste energy”. Does this mean that energy is actually lost? Explain.
Energy is never lost. An inefficient machine wastes energy by converting it to an unproductive state. A machine, such as a motor car engine has the primary task of converting the energy in the fuel to motion of the car. It is unproductive because a large proportion of the fuel 's chemical energy is dissipated in the form of noise, heat, vibration etc. so that only a small proportion is actually used for its prime purpose.
5. Is it possible for a simple machine to multiply both force and speed at the same time? Why?
It is impossible for a simple machine to multiply both force and gain speed at the same time. It is
EXERCISES 15
WORK, ENERGY, AND POWER
A. CONCEPTUAL QUESTIONS
1. Is work done when you move a book from the top of the desk to the floor? Why?
Yes. It is because the displacement of the book from the top of the desk to the floor and the force that is applied to the book is parallel with one another.
2. State the law of Conservation of Mechanical Energy in two ways?
The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant.
TMEinitial=TMEfinal
3. Explain the basic ideas that govern the design and operation of a roller coaster.
A roller coaster is operated and designed through the application of Physics. The law of Conservation of Energy governs the changes in a coaster 's speed and height. Simply put, the higher an object is off the ground, the more potential energy it has - that is, potential to gain speed as it falls. As it falls toward the ground, that potential energy changes to kinetic energy, or energy of motion. The sum of the two types of energy is constant, but a roller coaster must maintain an adequate balance of potential and kinetic energies to deliver a thrilling ride.
4. An inefficient machine is said to “waste energy”. Does this mean that energy is actually lost? Explain.
Energy is never lost. An inefficient machine wastes energy by converting it to an unproductive state. A machine, such as a motor car engine has the primary task of converting the energy in the fuel to motion of the car. It is unproductive because a large proportion of the fuel 's chemical energy is dissipated in the form of noise, heat, vibration etc. so that only a small proportion is actually used for its prime purpose.
5. Is it possible for a simple machine to multiply both force and speed at the same time? Why?
It is impossible for a simple machine to multiply both force and gain speed at the same time. It is