The GPS network consists of 24 satellites, each of which makes two orbits around the earth per day. Each satellite transmits a 50.0 (or even less) sinusoidal electromagnetic signal at two frequencies, one of which is 1575.42 . Assume that a satellite transmits half of its power at each frequency and that the waves travel uniformly in a downward hemisphere.

A)What average intensity does a GPS receiver on the ground, directly below the satellite, receive? (Hint: First use Newton's laws to find the altitude of the satellite.)
B)What is the amplitude of the electric field at the GPS receiver in part (a)?
C)What is the amplitude of the magnetic field at the GPS receiver in part (a)?
D)How long does it take the signal to reach the receiver?
E)If the receiver is a square panel 2.00 on a side that absorbs all of the beam, what average pressure does the signal exert on it?
F)What wavelength must the receiver be tuned to?

Positrons are spontaneously emitted from the nuclei of

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

Your starship, the aimless wanderer, lands on the mysterious planet mongo. as chief scientist-engineer, you make the following measurements: a 2.50-kg stone thrown upward from the ground at 14.0 m/s returns to the ground in 5.70 s ; the circumference of mongo at the equator is 2.20×10^5 km ; and there is no appreciable atmosphere on mongo. (a) the starship commander, captain confusion, asks for the following information: what is the mass of mongo? (b) if the aimless wanderer goes into a circular orbit 2.20×10^4 km above the surface of mongo, how many hours will it take the ship to complete one orbit? (c) an unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 44.0 km . to the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 23.0 m/s . if nothing is done to correct its orbit, with what speed (in km/h) will the spacecraft crash into the lunar surface?