Atrain with proper length l has clocks at the front and back. a photon is fired from the front to the back. working in the train frame, we can easily say that if the photon leaves the front of the train when a clock there reads zero, then it arrives at the back when a clock there reads l/c. now consider this setup in the ground frame, where the train travels by at speed v. rederive the above frame-independent result (namely, if the photon leaves the front of the train when a clock there reads zero, then it arrives at the back when a clock there reads l/c) by working only in the ground frame.

The intensity of a polarized electromagnetic wave is 12 w/m^2. part a) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=0∘ with the plane of polarization? part b) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=30∘ with the plane of polarization? part c) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=45∘ with the plane of polarization? part d) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=60∘ with the plane of polarization? part e) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=90∘ with the plane of polarization?

Aclarinetist, setting out for a performance, grabs his 3.350 kg clarinet case (including the clarinet) from the top of the piano and carries it through the air with an upward force of 24.65 n. find the case's vertical acceleration. indicate an upward acceleration as positive and a downward one as negative.

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?