A 50 cm long rod is placed against a vertical wall such that the bottom of the rod is 30 cm away from the wall. If the bottom of the rod is pulled horizontally away from the wall at 4 cm⋅s⁻¹, the top of the rod starts sliding down the wall with an instantaneous velocity (in cm⋅s⁻¹, rounded off to two decimal places) of magnitude _______.