Explanation:
Ubuntu is somewhat a South African concept that involves charity, sympathy, and mainly underlines the concept of universal brotherhood. Hence this concept can help fight social challenges such as racism, crime, violence and many more. It can contribute to maintaining peace and harmony in the country at large
formula for gravitational P.E =mgh
Solution:-mass=3kg height=5metre and gravity=9.8 or 10m/sec² so P.E=mgh , 3×9.8×5=147kgm²/sec²
Answer:
Light of a shorter wavelength should be used.
Explanation:
This is studied in the phenomenon called photoelectric effect, in which light is able to release electrons from a metal, said electrons are called photoelectrons .
The experiments that have been carried out show that <u>increasing or decreasing the intensity of the light will not cause the photoelectrons to be emitted</u>, what will cause the photoelectrons to be emitted is to increase the frequency of the incident light.
And a higher frequency corresponds to a shorter wavelength according to the equation:

(where
is frequency,
the speed of light, and
the wavelength)
So the answer is that the wavelength of the light must be shortened to cause the emission of electrones.
The time taken for the two balls to hit each other is 8 s.
The given parameters:
- <em>Acceleration of the rocket, a = 2 m/s²</em>
- <em>Length of the chamber, s = 4 m</em>
- <em>Speed of the first ball, = V1 = 0.3 m/s</em>
- <em>Speed of the second ball, V2 = 0.2 m/s</em>
The time taken for the two balls to hit each other is calculated by applying relative velocity formula as shown below;

Thus, the time taken for the two balls to hit each other is 8 s.
Learn more about relative velocity here: brainly.com/question/17228388