Hi Daniel,
we'll look into a way to easily create line breaks (maybe even within the text cell itself). In the meantime you can use the Coding block to define the variable, too.
This is the code that you can paste into the code block, which replaces the block defined in your example for now. Make sure that the capitalisation of the variables you created in Blockly (even if they're not used by blocks in the workspace) are the same in the Coding block, too.
Text1 = "t= " + t + " s \n Altitude = " + z + " m \n Speed = " + dz + " m/s \n Acceleration = " + a + " m/s2";

Cheers,
Stefan