in a local bar, a customer slides an empty beer mug down the counter for a refilll. the height of the counter is 1.36m. suppose that the initial velocity of this mug(when it leaves the counter) points to the horizontal direction. and the magnitude of its initial velocity is 2.5m/s. the mug slides off the counter and srikes the floor. what was the magitude of the mugs velocity before it hits the floor