The document you uploaded appears to be a set of physics problems related to various topics like orbital mechanics, electric fields, waves, sound, and magnetic fields. Here are the main questions from the document:

1. Orbital Mechanics Problem (A.1):
   a) Calculate the height above the Earth's surface and the velocity of a small artificial satellite orbiting the Earth every 90 minutes.
   b) Calculate the energy required to place the satellite into a new orbit 400 km above the surface.

2. Electric Field and Work Problem (A.2):
   a) Calculate the electric field vector at point A due to two charges placed at the vertices of a square.
   b) Calculate the work done by the electric field to move a charge from point A to point B.

3. Wave Propagation Problem (A.3):
   a) Determine the wave equation and the velocity of vibration at a specific point on a sinusoidal wave.
   b) Calculate the distance between two points with a phase difference of π/3 radians.

4. Sound Intensity Problem (A.4):
   a) Calculate the power of a shout emitted by a fakir.
   b) Determine the distance to the audience and the number of spectators, given various sound measurements.

5. Magnetic Field Problem (A.5):
   a) Calculate the magnetic flux through a square with side 1 meter in a uniform magnetic field of 5 T.
   b) Determine the relationship between electric and magnetic fields for uniform linear motion of a charged particle.

If you'd like, I can help you solve any of these questions. Which one would you like to start with?