The correct answer is:
<span>A. electron attraction between electron and nucleus = centripetal force of the orbiting electron
In fact, Bohr model depicts the atom as a nucleus surrounded by electrons in circular orbit around it, similar to the planets around the Sun. The centripetal force that keeps the electrons in circular motion around the nucles is provided by the electrostatic force between the electrons and the nucleus, so option A is the correct one.</span>
The elements that is very good in
electrical conductivity are gold and copper: elements that is amphoteric are
copper, zinc, tin, lead, aluminum and beryllium: elements that is gaseous at
room temperature are hydrogen, nitrogen, oxygen, fluorine and chlorine: elements
that is solid at room temperature are all metal except mercury and perhaps some
unseen radioactive elements. Lastly, elements that is brittle are hydrogen,
carbon, nitrogen, oxygen, phosphorus, sulfur and selenium
<h2>
Average speed of transit train is 60 mph</h2>
Explanation:
Average speed of passenger train = 45 mph
Time taken from station A to station B for passenger train = 10:00 - 6:00 = 4 hours
Distance between station A to station B = 45 x 4 = 180 miles.
Time taken from station A to station B for transit train = 4 - 1 = 3 hours
Distance between station A to station B = Average speed of transit train x Time taken from station A to station B for transit train
180 = Average speed of transit train x 3
Average speed of transit train = 60 mph
Average speed of transit train is 60 mph
