At what speed does the stone hit the ground in this problem?

Answer

It appears that the positive sense of the position h

the velocity at t = the initial velocity – 9.8 m/s per second it falls.

So here, with initial velocity, zero, you find -19.6 m/s after two seconds

You can also use the fact that the speed is the derivative of the place. So here it becomes v

In this way you can obtain the corresponding v

To find the speed on the ground you can first easily see how long the stone takes, by setting h

Then back -9.8 m/s per second you have

Try it!