How do I calculate the minimum force required to lift an object
l need to calculate the force and minimum machine operating weight required
to lift an object at one end, whilst it is supported at the other.The
object weighs 25,000kg and the object length is 25 feet.Essentially I am
simply lifting a solid block at one end whilst the other remains on the
ground.l need to raise it at one end to a height of 10 feet.l need to work
out the force required so l can ensure I am using a crane with an adequate
lifting capacity and operating weight.Does anybody have a formula l could use?l would guess it has something to do with levers and moments? Any help would be greatly appreciated.
crao_craz has the correct answer but by a laborious process.
By inspection the weight is centered at the center of gravity of the solid
block, or in the middle of the span, 12.5 ft. So just divide the weight by
2 to get the reaction at both ends, or 12500kg. If the object were a
different shape then the cg would be in a different location & a different
analysis using reactions & moments would be required. But if you need to
lift it at a certain rate other than very slowly then a different analysis would be also required using F=ma
This is an example of a ''second class'' lever. The situation
is the same as for the wheelbarrow. The force is applied at the end of
the handles, the weight is between the force & the fulcrum, & the fulcrum
is the wheel.
In this case, one end is where the lifting force will be applied; the
other end is the fulcrum, & the weight is at the center of gravity of the beam. If this is a uniform piece of metal, the center of gravity will be in the middle of the length, at the 12.5 ft. mark. The following notation is consistent with the second link. F1 is the lifting force. L1 is the distance from the lifting force to the fulcrum, 25 ft. F2 is the weight, 25,000 kg. L2 is the distance from the weight (center of gravity) to the fulcrum, 12.5 ft. F1*L1 - F2*L2 = 0 F1 = F2*L2 / L1 F1 = 25000 * 12.5 / 25 F1 = 12,500 kg This is not my usual type of work. (I am a geologist.) If you have any doubt about the correctness of this, I suggest you perform a scale model experiment. Weigh a board, then lift one end of it with a spring balance (fish scale). If the foregoing is correct, the balance should read one-half the board is weight.
the force = mass * acceleration
i think this is help for u
Don't you want to think in horsepower or SI units (which factor
in weight, lift and time).
To calculate the force, you use the formula: F=ma, where f is
the force , m is the mass and a is the acceleration due to gravity.
The minimum force required to move an object is called the limiting
friction.
Thinking back to school times, I recall a formula
Force=Mass*Acceleration. That is all I can remember, sorry!
this may help
http://epi-eng.com/BAS-ForceFrict.htm
by using laws of newton
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