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14 Cards in this Set
- Front
- Back
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Machine |
A machine is a device by which we can either overcome a large resistive force at some point by applying a small force at a convenient point and in a desired direction or by which we can obtain a gain in speed. |
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Load |
The resistive or opposing force to be overcome by a machine. |
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Effort |
The force applied on the machine to overcome the load. |
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Force multiplier |
M.A.>1 |
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Speed multiplier |
M.A.<1 |
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Work input |
The work done on the machine by the effort. |
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Work output |
The work done by the load on the machine |
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Lever |
A lever is a rigid, straight or bent bar which is capable of turning about a fixed point. |
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Class 1 lever |
Load and effort in same direction, fulcrum in between the both. Examples: Pliers, scissors, handle of water pump, crowbar, seesaw |
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Class 2 lever |
Load arm<effort arm Examples: bottle opener, bar to lift load, wheel Barrow, nut cracker |
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Class 3 lever |
Load arm>effort arm Example: Foot treadle, sugar tongs, knife, spade lifting a load |
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Pulley |
It is a metallic disc with a grooved rim. A string or rope is passing around the groove at the rim. The disc rotates about an axle passing through its centre. The axle is fixed rigidly to a frame by means of nails. |
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Single fixed pulley |
A pulley which has its axis of rotation fixed in position, is called a fixed pulley. |
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Single movable pulley |
A pulley whose axis of rotation is movable |
