Question
In practice, the work output of a machine is _____ the work input due to the effect of friction.
This question was previously asked in
RRB ALP 2018 CBT 2 Fitter Question Paper (21-Jan-2019) (Shift 3)
The correct answer is
always less than
In mechanical systems, especially in the realm of theoretical and practical machine operations, the concept of work input and work output is fundamental. Here is the step-by-step explanation of why the correct answer is "always less than":
- Understanding Work Input and Work Output:
- Work input refers to the energy supplied to a machine to perform a task.
- Work output is the useful work done by the machine when it uses the supplied energy.
- Role of Friction:
- Friction is a resistive force that acts opposite to the direction of motion.
- It converts some amount of input energy into heat, which is not useful for performing work.
- Efficiency and Energy Loss:
- Efficiency (\(\eta\)) of a machine is defined as the ratio of work output to work input, expressed as a percentage:
- \(\eta = \frac{\text{Work Output}}{\text{Work Input}} \times 100\%\)
- Due to friction and other resistive forces, not all input energy is converted into useful output, causing efficiency to always be less than 100%.
- Conclusion:
- Since a portion of input work is always lost to friction, the work output of a machine is always less than the work input.
Thus, the correct answer is "always less than" due to the inevitable loss of some energy to friction in real-world machines.
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