You have 8.0 hours to travel a distance of 140 km by bicycle. a-How long will it take you to travel the first half at an average speed of 15 km/h? b-In the second half of the ride, you need to increase your average speed to make up for lost time. If you can maintain an average speed of 25 km/h, will you be able to reach your destination on time?

Efficiency is an act of doing something

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 -

Electoral current force mechanical advantage if the wheel and axle is 2 n and the output force is 20 n