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प्रश्न
Define the term efficiency of a machine.
उत्तर
It is the proportion of the machine's useful work to the effort's input into the machine.
Efficiency η = `"Work output"/"Work input" xx 100%`
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संबंधित प्रश्न
Explain the term mechanical advantage.
When does a machine act as (a) a force multiplier, (b) a speed multiplier? Can a machine act as a force multiplier and a speed multiplier simultaneously?
- State the relationship between mechanical advantage, velocity ratio and efficiency.
- Name the term that will not change for a machine of a given design.
How is the mechanical advantage related with the velocity ratio for an actual machine? State whether the efficiency of such a machine is equal to 1, less than 1 or more than 1.
Draw diagrams to illustrate the position of fulcrum load and effort, in the following:
A seesaw
Draw a diagram to illustrate the position of fulcrum load and effort, in the following:
Forceps
Figure below shows a wheel barrow of mass 15 kgf carrying a load of 30 kgf with its centre of gravity at A. The points B and C are the centre of wheel and tip of the handle such that the horizontal distance AB = 20 cm and AC = 40 cm.
Find:
- the load arm,
- the effort arm,
- the mechanical advantage and
- the minimum effort required to keep the leg just off the ground.
A fire tongs has arms 20 cm long. It is used to lift a coal of weight 1.5 kgf by applying an effort at a distance 15 cm from the fulcrum. Find:
- the mechanical advantage of fire tongs and
- the effort needed.
A machine works as a
- force multiplier,
- speed multiplier.
In each case, state whether the velocity ratio is more than or less than 1.
Mechanical advantage = ______ × velocity ratio.
