Workers pushing a 180 kg trunk across a level floor encounter a 10 m long region where the floor becomes increasingly rough; the coefficient of kinetic friction increases from μ0 = .17 to .79 according to the expression ( μk = μ0 + ax^2 ) where a = 0.00062 m^-2, and x is the distance in meters from the beginning of the rough region.
how much work does it take to push the trunk at constant speed across the region?

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )

firearm identification is the process of analyzing the bullets and cartridge cases left at a crime scene to determine if they came from a particular firearm. marks on the bullets and cartridges may be common to every firearm of that type. these are called class characteristics.