Ball bearings are made by letting spherical drops of molten metal fall inside a tall tower—called a shot tower—and solidify as they fall. (b) What is the bearing's impact velocity?

Video transcript

Hey, everyone in this problem, an experimental setup is used to create calcium alga Nate spheres by allowing an alga Nate solution droplet to fall from the tip of a syringe into a calcium chloride bath solution. The droplet strikes the bath solution 0.25 seconds later and were asked to determine the velocity of the droplet just before striking the bath solution. Alright. So this is a typical motion problem. Okay. We're gonna use our um equations are Kinnah Matic equations. If that's what you like to call them, let's write out what we know first And we know that this droplet is going to fall from the tip of a syringe. So the initial speed of the droplet is going to be 0m/s, the final speed. Well, this is what we're looking for the speed right before it hits the bath solution, the acceleration it's falling. And so we have the acceleration due to gravity, we're going to take upwards as our positive direction or positive y direction. And so the acceleration will be negative 9.8 m per second squared. We know that the time it takes is 0.25 seconds and we aren't given any information about delta Y que the height or the distance that it falls. So we have three values that we know V not A and T we want to find V F. We can go ahead and use our equations. We're going to choose the equation without delta Y because we don't have information about delta Y and it's not the quantity that we're looking for. We have the following equation V F is equal to V naught plus 80. Okay. V F is what we're looking for That's equal to v naught which is zero. So that term goes away the acceleration negative 9.8 meters per second squared times the time, 0.25 seconds. And we get a V F value of negative 2.45 m per second. Okay. The units here we have meters per second squared times a second, gives us meters per second. The unit we want four velocity. So our final velocity is negative 2.45 m per second. Now the negative indicates that we're going downward. Okay. We've chosen positive to be our upward to be our positive direction, which means a negative value indicates we're going downwards. And that makes sense. The droplet is falling and so its velocity is downwards right before it hits that bath solution. So looking at our answer choices, we found a speed of approximately 2.5 m/s and the velocity the direction is downwards. And so we have answer choice B that's it for this one. Thanks everyone for watching. See you in the next video.