Normal force, friction force, gravitational force
Answer:
#See solution for details.
Explanation:
-Chemical energy in the battery is converted into Electrical Energy which powers up the phone.
-The electrical energy is then converted to Light Energy when the phone is powered up, this is seen through the lightening up of the phone screen.
-During phone calls, the electrical energy is further converted to Sound Energy to allow for transmission of audio signals.
- As we continue to use the phone, the electrical energy is converted into heat energy which we feel due to an overheating battery.
-The cycle then repeats itself again whenever a phone is charged.
The answer would be Newton’s Second Law
A "screen" or even just a set of parallel bars are highly reflective to electromagnetic waves as long as the open spaces are small compared to the wavelengths.
"Grid" dishes work fine ... with less weight and less wind resistance ... for frequencies below about 3 GHz. (Wavelengths of at least 10 cm.)
(I even worked on a microwave system in South America where huge grid dishes were used on a 90-mile link.)
