 This question guys, it's given that a car is moving with a certain velocity and it comes to a halt after covering 62.5 meters. Okay, so this is important information. If the retardation was five meter per second squared, then find the initial velocity of the car. So retardation is a keyword and initial velocity is my demand of the question. Okay, so as we have discussed, always draw a representative diagram for the given case. So let's say it looks a little different. Let me write again, okay. So let us say this is point A, the starting point and this is B, the final point, right? Here, let's say the, what all the information is given. So this is given that this distance S is 62.5 meters. What else is given? So let us take, yeah, so here T is equal to zero and here T is equal to, how much time is given? Not given, so let's say T, T is not found. U in this direction, not known. V is known. What is V? Zero, comes to a halt. So in the diagram, we represented everything. Okay, have we got any other information? Yes, we have acceleration. Now here is the error zone. What happens? Many people will take simply, right? Five meter per second square, but the acceleration is minus five meter per second square. Why is minus? Because the velocity is coming from non-zero value to halt, it is coming to halt. So hence it has to be a case of retardation or deceleration. So this is the thing. So hence always remember, error zone. What is the error zone in this problem? Retardation, retardation has to be opposite of, opposite of velocity, right? Or the direction of acceleration is opposite of velocity. So hence you have to consider negative sign. If you have taken velocity as positive, consider negative sign. Okay, if you miss it, then you lose marks, fair enough. Now let's go ahead and solve. Okay, so U is not known, so right U is unknown. V is clearly zero. A is clearly minus five meter per second squared. And S is given 62.5 meters. So clearly, which one, which application or which equation of motion you will use? So what all do we have anyways? We have V is equal to U plus 80. And S is equal to UT plus half AT square. Now there is no mention of time here. So we will try to avoid timing, right? So V square is equal to U square plus two AS. Now this is the equation of our choice. V square is equal to U square plus two AS. Or the third one, why? Because there is no mention of time over there. So V square is equal to U square plus twice AS. V square we know, zero. What is U square? This is what we have to find out. Plus two AS, so plus two into A minus five into S, which is 62.5. Okay, so U square is equal to, right? 10 and 625. Okay, so now clearly U is root of 625. And we'll take only positive value, not the negative value. Why? Because in this direction, we have considered positive U. So we are assuming that the velocity was positive in this direction. So hence, since A is negative, so hence this positive and acceleration negative is the right combination. If you take U as negative, then what will happen? That means you are saying that U was like this. So how can some body which is moving in this direction come to a halt here? Not possible, correct? So U is clearly 25 meter per second. And this is our solution. It was fairly simple question. So you have to just pick up one of the three equations depending upon whatever data is given. Do the calculations carefully. Keep in mind the error zones. Error zones is this. And another error zone which we have discussed previously is that do not, again I'll highlight, do not miss, do not miss the units. Do not miss the units, that will be disastrous. Do not miss the units, okay? That's how you should solve this question. So let's meet again in the next question. Thank you.