Answer:
See explanation below
Step-by-step explanation:
Let's recall what's the law of acceleration.
First of all, the acceleration is a vector that has the change of velocity in function of the time.
Now, the law of acceleration is related to Newton's Second law which states that an object will move only if there are forces around it. In other words, the following expression:
F = m . a
Now, in this case, we know that the acceleration of an object is affected by a force always. So, if an object stand still, it will not move unless you push it or pull it to move, and the acceleration will speed up or down depending of the force it was exerted.
According to this, the law of acceleration can be applied here:
1. A bike going down a hill. Of course, because, let's suppose you let a bike alone go down on a hill, you will see that the speed of the bike will be faster as time goes by. This is because the force acting here is the weight of the bike and gravity.
2. Dropping a ball from a building. In this case, you drop a ball from a high floor on a building, it will happen the same thing as the bike. It will go faster because of gravity.
3. Putting the break on a car. Now in this case it's easy because you only need to know that when you put the brakes, the speed of the car will go down, but also the acceleration. So there's no need of a further explanation of this.
Hope this helps