Imagine a piece of conducting wire with qurrent i and eross section a and a negative oharge q at a distance of r from the center of the wire. now uging two different reference frames: (1) where the charge q and the negative ourrent carriers in the wire are both moving to the right with velootty vand (u) where the wire itself moving with velocity v to the left and the charge q in stationary, show that the force experienced by the charge in exactly the same.

You have been hired to design a spring-launched roller coaster thatwill carry two passengers per car. the car goes up a 10-m highhill, then descends 15m to the track's lowest point. you'vedetermined that the spring can be compressed a maximum o 2.0m andthat a loaded car will have a maximum mass of 400kg. for safetyreasons, the spring constant should be 10% larger than the minimumneeded for the car to just make it over the top. a) what spring constant (k) should you specify ? b) what is the maximum speed of a 350 kg car if the spring iscompressed the full amount.