Answer:
The speed decreases.
Explanation:
This can be explained using the conservation of linear momentum.
Since there is no friction, the initial moment of the train must be equal to its linear moment after it is filled with water.
the initial linear momentum is

where
is the initial mass of the train, and
the initial speed of the train.
And linear momentum after the water filled the train car is

where
is mass of the train after the rain, and
the speed of the train after the rain
<u>the equality must be fulfilled:</u>

We know that if water is added to the train,
that is the mass after the water is added, is greater than
which is the mass of the train without the water.
Therefore, in order for the conservation of the linear momentum to be fulfilled: 
the speed after the water is added (
) must be smaller than the initial train speed (
) . So the speed of the car decreases.
Answer:
9.8m/s²
Explanation:
The acceleration of the ball thrown after leaving my hand is 9.8m/s². This will be the acceleration due to gravity on the body.
- Acceleration due to gravity is caused by the pull of the earth on a massive object.
- The value of this acceleration is 9.8m/s².
- As the ball nears the surface, it comes near zero.
Yes. Even greater. Air resistance or drag becomes harder the faster an object goes. This is why when cars reach their max speed they don't accelerate as fast, because they are pushing harder against the wind. If I take a tennis ball and shoot it down a bottomless pit, a 400 kph, the drag will slow the ball down till it reaches terminal velocity.
epicycles were orbits within orbits used to explain discrepancies between expected and observed planetary movement, including the appearance of planets slowing down, speeding up, and moving backward.