As a head-up, it is important to notice that a white dwarf only shines thanks to the stored energy and light, because a white dwarf doesn't have any hydrogen left to perform nuclear fusion.
Now the process:
First, the white dwarf accumulates all the extracted matter from its companion, onto its own surface. This extra matter increases the white dwarf's temperature and density.
After a while, the star reaches about 10 million K, so nuclear fusion can begin. The hydrogen that has been "stolen" from the other star and accumulated in the white dwarf's surface it's used for the fusion, dramatically increasing the star's brightness for a short time, causing what we know as a Nova.
As this fuel its quickly burnt out or blown into space, the star goes back to its natural white dwarf state. Since the white dwarf nor the companion star are destroyed in this process, it can happen countless of times during their lifespan.
Answer:
"Non-uniform velocity" occurs when<em> an object changes its velocity </em>upon motion. This happens when the object either accelerates or decelerates <em>(negative acceleration)</em> in its speed or changes its direction.
Explanation:
"Velocity" refers to<em> speed with a specific direction. </em>
If the velocity is uniform, there's<u> no change in speed and direction</u>. However, if changes occur on either the speed, direction or both, then <em>the velocity becomes </em><u><em>variable or non-uniform.</em></u>
For example, when it comes to a moving car, it is said to be in non-uniform velocity if <em>the distances covered is unequal in relation to the equal intervals of time.</em>
Answer:
Option 5. 1 and 3
Solution:
The only forces acting on the tennis ball after it has left contact with the racquet and the instant before it touches the ground are the force of gravity in the downward direction and the force by the air exerted on the ball.
The ball after it left follows the path of trajectory and as it moves forward in the horizontal direction the force of the air acts on it.
In the whole projectile motion of the ball, the acceleration due to gravity acts on the ball thus the force of gravity acts on the ball in the downward direction before it hits the ground.
