Only two forces acts on the traffic light: the tension T of the cable (upward) and the weight of the traffic light (downward). The weight is
If the traffic light is at equilibrium, the resultant of the two forces must be equal to zero (Netwon's second law):
Therefore the tension of the cable is
Pe = m • g • h
= 100 • 9.8 • 20
= 19,600 or 1.96 x 10^4
It is not possible to see the other waves on the electromagnetic spectrum because only other species can see the other parts of the spectrum because they have different components in their eyes than we do, therefore, only allowing us to see a
portion of the spectrum, which is visible light.
You use the right hand rule. With your thumb out and the rest of your fingers curved ( like a thumbs up) curve your fingers to the direction of the torque. The direction your thumbs points at is the direction of the torque