C.
The train first sped up, giving it a positive acceleration in the beginning. This eliminates D since that choice states that it begins with a negative acceleration. This also eliminates B since that choice states that the train only had a negation acceleration.
Next, the train slows down, giving it a negative acceleration. We’re looking for the answer choice that starts with a positive acceleration and ends with a negative one. This makes C the correct answer. Hope this helps!
Answer:
Having a bigger angle above the horizontal
Explanation:
Applying the energy conservation theorem:

The kinetic energy is reduced because of the work done by the friction force.
The friction force is given by:

so the friction force depends on the Normal force, because the slide has an angle the normal force is given by:

So when the angle of the slide is bigger, the friction force decreases, for example:
for 45 degrees:

for 75 degrees:

as you can see if the angle is bigger above the horizontal, the friction force is reduced and so the work done by that force. We didn't have to change the height of the slide, so the potential gravitational energy remains the same.
Answer:
They create electricity from the sun's rays
Explanation:
By the use of "solar cells" or "solar panel", you can trap solar energy in silicon/germanium rods, then you can convert in into electricity too. Solar powered panels convert the sun's rays into electricity by exciting electrons in silicon cells using the photons of light from the sun. This electricity can then be used to supply renewable energy to your home or business.
Answer: 2
Explanation:
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.