<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.
Look, according to newton’s law of the conservation of mass power, the principle behind the electric generator would be when a conductor is moved in a magnetic field than the current is moved buh the conductor
The correct option is D.
Resonance is a phenomenon in which a vibrating system or an external force induces another system to vibrate at greater amplitude at particular frequencies.
When a tuning fork is struck with another object, the tuning fork will start to vibrate as a result of the force that is exerted by the object used to struck it. This type of vibration, without direct excitation by a man is an example of resonance.
Answer: D. The object would have an acceleration of 6 m/s/s to the right.
Explanation:
I got it right on USA test prep
We have no way to say what the illustration represents, mainly because
you haven't given us a way to see the illustration.
<span>However, the process that all stars, including our sun, use to continuously
produce energy is nuclear fusion.</span>