4. Open the lab interactive and run a few trials changing the variables each time. Decide which vanable you want to change in order to make a strong electromagnetand record it here. This will be your independent vanable.

Aroll in a paper machine is powered by a separately excited dc machine. operating point 1 (under load): the roll typically operates at 764 rpm and must provide 301 nm of torque to oppose the load of the paper. the armature voltage is 230v for this operating point operating point 2 (no load): when the load is removed the speed of the roll increases to 900 rpm (the field characteristics are unchanged) la ea dev m (a) calculate the maximum torque (units of nm) that the motor can supply with this applied voltage (b) calculate the value of the armature resistance, ra (in ohms) (c) at operating point 1 (loaded condition), the field current, i, and the total input power (armature field), are measured to be to be 10 a and 28,600 w respectively. use this information to calculate the value of the field resistance, rf (in ohms). (d) (d) at operating point 1 (loaded condition), calculate the motor efficiency. express your answer as a percent to at least 2 significant digits. (d) if the field voltage is reduced by 1/2, calculate the new stall torque (in nm) of the motor (f). if the field voltage is reduced by 1/2, calculate the new no-load speed (in rad/sec)

Utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must available hint(s)utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must pump water back into their cells to counter its loss due to osmosisactively pump water back out of their cells to counter its inflow due to osmosissynthesize membranes that are impermeable to substances that upset osmotic balanceactively pump salt back out of their cells to counter its inflow due to osmosis

Convection currents are caused by differences in what two things?