A student pulls a box of books on a smooth horizontal floor with a force of 100 N in a direction of 37° above the horizontal. If the mass of the box and the books is 40.0 kg, what is the normal force of the box?

1) when you rub your hands together quickly, the kinetic energy is converted to mechanical energy.2) thermal energy from the sun travels to earth as infrared waves.3) energy is transferred through the matter of space by electromagnetic waves. 4) when a match is burned, chemical potential energy is converted to thermal and radiant energy. 5) seismicwaves are caused by back and forth movement , or vibration, of an object. 6) mechanicalenergy in an engine changes thermal energy into kinetic energy to make a car move.

Ithink it is letter b, i may be wrong but i think that is the answer

It really doesn't matter for any of the questions that you've listed.

F  you double the  force, you double the acceleration, but  if  you double the  mass, you velocity. all bodies accelerate at the  same  rate regardless of size or  mass.