A block of mass m=1.0 kg is initially at rest at the bottom of a ramp of length l=10m. The ramp is tilted upwards at an angle of 30 degrees and the coefficient of kinetic friction is 0.4. The block is connected to a rope and pulley as shown in the figure. If the rope is pulled with a force of 5N, how long does it take the block to reach the top of the ramp? You can ignore static friction, but not kinetic friction.

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -

Is there a picture to go along with this