ok so if a crane lifts a 500 kg mass to a height of 20m in 40 seconds what is the work done by the crane, the output power at the cranes hook ad the input power to the electrical motor if the combined efficiency is 0.8?alsoIf a 50kg mass is raised vertically through a height of 40m in 20s what is its energy in the raised position and what power was developed in raising the load?Thankyou in advance
StrippersNot women, but clips if you have the little adapter and stripper clips you can load mags in no time and not have to worry about any feed issues, yet still have piece of mind
why does this need to change if they are safe whre they are ? the loading out of its box into a stell shell?
Depends what ammunition you're talking aboutIf you're talking about .223 it will be fine since the rounds do not exert enough pressure to bend the feed lipsIf you're talking about 6.8 get a high quality mag, I left mine loaded in a c products and it destroyed the lips to the point where I can't use itI had to spend 43 on a pri magazine and I haven't had any problems with them, no bends, no dents, nothing.
no calc on me but its done like this 1Work for this problem is force times distanceThe force is mg and distance is 20mMultiply them together and remember the answer is positive because the mass is moving in the same direction as the force applied by the craneUnits are Joules2Power is work divided by timeSo divide the answer from number 1 by 40 secondsUnits would be in J/s, which is Watts3The crane only has 80% efficiencyThis means that for however much power the motor supplies, only 80% is converted into the work of lifting the craneDivide your answer from number 2 by .8 and the units are still Watts4We will take the mass' position before it is raised to be that of zero gravitational potential energyAfter it reaches its may height, its energy (V) is equal to mgh, where h is the height of the mass above its starting positionThe answer will be in JoulesDivide that by 40 seconds and it will give you the power which is in WattsThe power should be 4 times that which we got in question 2.
