An LRT train consisting of 4 cars is crossing the bridge from the U of A to downtown Cars 1, 2 and 3 all have a mass of 4.0*10^ 4 kg Car 4 has more passengers , so it has a mass of 4.5*10^ 4 kg . The train accelerates as it crosses the bridge at a rate of 0.25 m/s ^ 2 , north . Determine the force that car 4 exerts on car 3 during this period (/4)

Light from two different sources are incident upon the same side of a polarizing filter. light from one source is polarized with total intensity ip, while light from the other source is unpolarized with total intensity iu. as you rotate the polarizing filter through 360 degrees, the intensity of the transmitted light on the other side varies by a factor of 9. what is the relative intensity of the initial polarized source to the unpolarized source, or ip/iu?