What is Acceleration?

What is Acceleration? Acceleration is how fast an object increases its speed. For example, if a train maintains a constant speed, but never changes speeds, the train has no acceleration. During our lab, we altered the ramp, to make the cart go up the ramp. When we pushed the cart up the ramp, the gravatational pull caused the speed of the cart to increase on the way down, rather on the way up. In that case, the acceleration was faster on the way down, rather when we pushed the cart up the ramp.