Physics
Select the incorrect statement:
- A machine always has efficiency less than 100%.
- The mechanical advantage of a machine can be less than 1.
- A machine can have mechanical advantage greater than the velocity ratio.
- A machine can be used as a speed multiplier.
Machines
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Answer
A machine can have mechanical advantage greater than the velocity ratio.
Reason — In actual practice, mechanical advantage for all practical machines is always less than its velocity ratio (i.e., MA < VR) or the output work is always less than the input work, so the efficiency is less than 1 (i.e., η < 1 ) due to some loss of input energy against the force of friction etc.
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Related Questions
Which of the following relations is wrong?
- Work input = Effort x Displacement of effort
- Work output = Load x Displacement of load
- Efficiency = Work input / Work output
- Mechanical advantage = Velocity ratio x Efficiency
If the effort needed is less than the load, then mechanical advantage of the machine is:
- Greater than 1
- Less than 1
- Equal to one
- None of these
The lever for which mechanical advantage is less than 1 has:
- Fulcrum at the mid-point between load and effort.
- Load between effort and fulcrum.
- Effort between fulcrum and load.
- Load and effort acting at the same point.
Class II levers are designed to have:
- M.A. = V.R.
- M.A. > V.R.
- M.A. > 1
- M.A. < 1