sldemo_bounce example shows how to use the Second-Order Integrator and Memory blocks to capture the velocity of a bouncing ball just before it hits the ground.
Because Inherit sample time is not selected for the Memory block, the block sample time depends on the type of solver for simulating the model. In this case, the model uses a variable-step (ode23) solver. Therefore, the sample time of the Memory block is continuous but fixed in minor time step: [0, 1]. When you run the model, you get these results.
If you replace the Memory block with a Unit Delay block, you get the same results. However, a warning also appears due to the discrete Unit Delay block inheriting a continuous sample time.
For more information, see the model description.