Copper and aluminum are being considered for a high-voltage transmission line that must carry a current of 56.4 a. the resistance per unit length is to be 0.181 ω/km. the densities of copper and aluminum are 8960 and 2600 kg/m3, respectively. compute (a) the magnitude j of the current density and (b) the mass per unit length λ for a copper cable and (c) j and (d) λ for an aluminum cable.

World class speed skaters can skate a 3,000-m course in about 4 minutes. what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s

A3030 cmcm wrench is used to loosen a bolt with a force applied 0.30.3 mm from the bolt. it takes 6060 nn to loosen the bolt when the force is applied perpendicular to the wrench. how much force would it take if the force was applied at a 3030 degree angle from perpendicular? a 3030 cmcm wrench is used to loosen a bolt with a force applied 0.30.3 mm from the bolt. it takes 6060 nn to loosen the bolt when the force is applied perpendicular to the wrench. how much force would it take if the force was applied at a 3030 degree angle from perpendicular?

Consider two regions of space containing a static electric field, region a and region b. in region a the equipotential lines are more closely spaced than those in region b. what can be said about the relative strength of the electric field in the two regions? a) the electric field in region a is stronger th