A student wanted to prepare 1 liter of 0.01M, PH=3, Buffer from a weak acid (HA). To do so he had 1M HA Pka=2.3 and 1M of NaOH
solution. Unfortunately, the water he had used were found to be
contaminated and became to be a 0.5mM HCl solution (without his
knowledge). What will be the PH of the Buffer in these terms?

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied