Copper and aluminum are being considered for a high-voltage transmission line that must carry a current of 51.5 a. the resistance per unit length is to be 0.144 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.

Aspecial electronic sensor is embedded in the seat of a car that takes riders around a circular loop-the-loop ride at an amusement park. the sensor measures the magnitude of the normal force that the seat exerts on a rider. the loop-the-loop ride is in the vertical plane and its radius is 23 m. sitting on the seat before the ride starts, a rider is level and stationary, and the electronic sensor reads 740 n. at the top of the loop, the rider is upside down and moving, and the sensor reads 370 n. what is the speed of the rider at the top of the loop?

Density of salty water as compared to the density of pure water is(a) is less(b) is always equal(c) is always more(d) may be less or more

Velocity is a description of both speed and direction, therefore it - a vector - a force arrow - the same as acceleration - a magnitude