How is a linear slide held over a platform? What are the design considerations given to the structure of the platform? To make the motion of the slide incrementally continuously variable, what device and components would need to be used? How do you turn rotary motion into linear motion? What are the design factors that go into which type of drive mechanism to choose? When a cart is moving on the linear slide, it tends to rotate about the axis, how do you resolve this issue? How do you test whether this resolution works?