Consider two force vectors in the xy-horizontal plane. Suppose a force of 11.7 N pointing along the x-axis is added to a second force of 18.1 N directed at 55 degrees to the x-axis , also in the horizontal plane. Find the resultant vector for this sum.

Aparticle of mass m is placed in a one-dimensional box of length l. the box is so small that the particle’s motion is relativistic, so that e p2/2m is not valid. (a) derive an expression for the energy levels of the particle using the relativistic energy–momentum relation and the quantization of momentum that derives from connement. (b) if the particle is an electron in a box of length l 1.00 1012 m, nd its lowest possible kinetic energy. by what percent is the nonrelativistic formula for the energy in error?