Abook resting on a table has a weight of 45n. what is fn? what is fg?

Since it is on a flat table, the normal force is equal to its total weight, FN=45N.  This is the force the table applies to the book. The force that is causing the 45N downward is gravity, which is FG=-45N.  I say negative because the force of gravity is down.  So FN and FG are equal and opposite forces.  They add to zero, which according to Newton's second law, F=ma, means that if the net force is zero, 0=ma.  Since m is not zero, a must be zero.  In other words, the book is not accelerating, it is sitting still on the table.

4. 50x10= 500m/s 5. 52m/s