what are two examples of tasks for which each kind of magnet would be suitable?
First covert all dimensions to metricThe mix of diffferent units is to confuse youUse density to calculate volume since you are given the mass1 oz28.35g, 1 ft30.48 cm, 75 ft^ 8.66 ft x 8.66 ft 19797.34cm ^2 Density mass/ volume vol 28.35 x 12/2.70126 cm^3 vol area x thickness so thickness vol/area 126/(19797.34)^2 cm covert to mm x 10 to convert to km /100
Ask your Chemistry teacher, they are trained in that area of science.
It would be helpful if you mentioned what kinds of magnet your out-of-context pasted question was aboutElectro vs permanent? AC vs DC? Bar vs horseshoe? I'll assume electro vs permanentA typical electromagnet example is the large type used in junkyards to separate iron-based metals from othersThis magnet is lowered by a crane onto a pile of mixed metal scraps and then turned onIt picks up the iron-based scraps and then is moved over a dump truck, where it is turned off so it drops the scraps into the truckThe ability to pick up and drop on a simple command (turning on/off) makes such magnets very valuable toolsA permanent magnet is useful anywhere a steady magnetic field is desiredRefrigerator magnets and field magnets for small motors are examplesThese magnets save electric energy that would be needed if an electromagnet were used.
