Consider a wire of a circular cross-section with a radius of r = 3.03 mm. the magnitude of the current density is modeled as j = cr2 = 5.25 ✕ 106 a/m4 r2. what is the current (in a) through the inner section of the wire from the center to r = 0.5r?

Explanation:

As we know that current in a wire depends on its current density and given as

so we have

so we will have

now we have to find current in r = 0.5 R

so we have

now plug in all data

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2

the right answer is 0.3 meters per second