[Music] hello everyone welcome to physics demos today I have two dimensional motion demo for you in this demo you see two steel balls one will be dropped vertically the second one will be shot horizontally which one do you think will hit the bottom first the one that drops vertically or the one that's been fired horizontally let's see what happens alright this has been locked and ready to go from the sound of the steel ball dropping the hip ground at the same time we heard those two balls hitting the ground at the same time so why do you think they hit the bottom at the same time in terms of vertical both of them have initial vertical velocity to be zero they covered the same displacement vertically and they're falling at the same rate of 9.81 m/s^2 vertical motion is independent of horizontal motion that ball to my left was fired in that direction to my left it had velocity in horizontal direction however in terms of vertical it had the same velocity as this ball on my right hand side so that's why they would hit the bottom at the same time you