What increases the work output of a machine?
Only way to increase work output is to increase the amount of work you put into the machine.
What is the percentage of input work that is converted to output work?
Ch 4 Vocabulary
| Question | Answer |
|---|---|
| The force exerted on a machine. | input force |
| The force exerted on an object by a machine. | output force |
| The number of times the force exerted on a machine is multiplied by the machine. | mechanical advantage |
| The percentage of input work that is converted to output work. | efficiency |
Is determined by dividing work output by work input?
Physical Science – Chapter 8 – Work and Machines
| A | B |
|---|---|
| mechanical efficiency | a comparison-expressed as a percent-of a machine’s work output with the work input; can be calculated by dividing work output by work input and then multiplying by 100 |
| fulcrum | the fixed point about which a lever pivots |
Is there a 100% efficient system?
Heat, sound, and mechanical energy are all unwanted byproducts. So if you put in 100 watts of power and get 50 watts of light the system is 100% efficient. There is a principle called “unity efficiency” that can allow you to produce MORE than 100% of the input.
Why is Carnot cycle not possible?
Carnot cycles are not encountered in reality since achieving isothermal heat transfer is very difficult (needs very large heat exchangers and long time). Also process 3-4 requires a pump or compressor that can handle two phase mixture (liquid and vapor) which is impractical.
Why is Carnot cycle ideal?
The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws. When the second law of thermodynamics states that not all the supplied heat in a heat engine can be used to do work, the Carnot efficiency sets the limiting value on the fraction of the heat which can be so used.
What are the four process of Carnot cycle?
Name the processes involved in Carnot cycle? It involves four process: isothermal expansion, adiabatic expansion, isothermal compression and adiabatic compression.
Which cycle has highest efficiency?
Explanation: Otto cycle is more efficient than Diesel cycle for a given compression ratio. 6. For constant maximum pressure and heat input, the air standard efficiency of the gas power cycle is in the order.
What is the efficiency of diesel cycle?
A typical diesel automotive engine operates at around 30% to 35% of thermal efficiency. About 65-70% is rejected as waste heat without being converted into useful work, i.e. work delivered to wheels. In general, engines using the Diesel cycle are usually more efficient, than engines using the Otto cycle.
What is single cycle efficiency?
2.5. The single cycle efficiency is defined as the ratio of discharge capacity to charge capacity in a single cycle, regardless of the self- discharge loss. Fig. 2.18 compares the single cycle efficiency of various energy storage systems, which can be divided into two categories: Figure 2.18.
What is the efficiency of a simple cycle gas turbine?
A simple cycle gas turbine can achieve energy conversion efficiencies ranging between 20 and 35 percent. With the higher temperatures achieved in the Department of Energy’s turbine program, future hydrogen and syngas fired gas turbine combined cycle plants are likely to achieve efficiencies of 60 percent or more.