A 0.3-kg mass is connected to the top of a 50-cm vertical shaft by a 30-cm string, and to the bottom of the shaft by a 40-cm string. The shaft rotates 3.0 times per second. Find the tension in each string.

The answer is frictional force

Because its reliable.   there is no pollution  the chances of a radiation leak is low

Ibelieve the answer is b

Two 10¢  coins  (dimes)  carrying identical charges  are  lying 2.5 m apart  on a  table.  if each  of  these coins experiences  an  electrostatic force  of  magnitude 2.0 n due  to the  other coin.  the charge on each coin is :     52.2 uc