<u>The answer is not contained detail explanation, just a solution and the required values. </u>
All the details are in the pictures, the answers are marked with orange colour.
Note,
in the task no 20.:

V - the velocity of the pair of the balls after collision.
in the task no 21:
m₁ - the mass of the copper ball; m₂ - the mass of the copper calorimeter; m₃ - the mass of the water; t₀ - the initial temperature of water in the copper calorimeter; θ - the final temperature in the calorimeter after the copper ball is transferred into a copper calorimeter; t₁ - the required initial temperature of the copper ball before it is transferred into the calorimeter.
Answer: No
Explanation: colour of substance appears when molecules of apple
Absorb wavelengths of counter colour, also green light.
Counter colours are green-red, violet -yellow and blue-orange
Answer:
T² ∝ R³
Explanation:
Given data,
The period of revolution of the planet around the sun, T
The mean distance of the planet from the sun, R
According to the III law of Kepler, " Law of Periods' states that the square of the orbital period to go around the sun once is directly proportional to the cube of the mean distance between the sun and the planet.
T² ∝ R³

From the above equation it is clear that T² varies directly as the R³.
True no object can travel faster than speed of light