Speed from object moving by timeline

Hi, I have an object that moves up and down by using a timeline, now I have to get the speed of the object so I can use this speed to move other objects. In the blueprint I used a math equation to calculate the speed, I have the displacement in Z and I divide that by delta seconds. But now for example like you can see on the picture, I have a displacement of 30cm which results in a speed of 1800. But this isn’t correct because the object moves from 0 to 30 cm in 0,5 seconds. So how can I get the right speed from the object?