Question

b) Determine the force the sun exerts on a kilogram of water on the earth’s surface at a point nearest the sun and at a point farthest from the sun. (c) Do the same for the force exerted by the moon. (d) Explain why the tides are associated with the motion of the moon.

Answer 1

We know that the gravitational force of attraction between the two bodies of masses m1,m2, sepatared by a distance of r is F= Gm1m2/r^2
b)      ((G*m) / (R - R_e^2) - ((G*m) / (R + R_e)^2)
  

C)   NO

d)   Because water is cohesive, it tends to act together like a single body or mass.  

   As the earth rotates,it is subjected to a centrifugal force which pulls the ocean water molecules away from the earth's surface
  

   If the earth s$imply rotated on its own axis, then even though there would be this bulge there would be no tide. However, because the moon is very close to the earth, its gravity exerts an effect on the rotational system of the earth,
   causing it to also rotates in tandem with the moon on a different axis. This rotation is like the rotation of a baton, with the earth and moon each representing on of the balls on the end of the baton. Because of this additional rotation,
   there is an additional centrifugal force exerted on the side of the earth that is away from the moon
   Thus, the centrifugal force is greatest on the side of the earth that is away from the moon, and there is a greater bulge in the water on that side.
  

   The moon affects the tides depending on its position around the earth. For example, if the sun, the moon and the earth are all lined up in a straight line (180 degree angle) then they form tides call SPRING TIDES
   The Earth's tides are about the same whether the Sun and Moon are lined up on opposite sides of the Earth (full moon phase) or on the same side (new moon phase). During spring tides you will notice higher and/or lower tides than normal.
   When the earth, sun and moon form right angles (occurs when the moon is at the first quarter or last quarter phase) to each other they form tides called NEAP TIDES. Neap tides are generally weak tides