1D Kinematics Legacy Problem #7 Guided Solution

Many beginning students of physics often think that to solve a problem effectively, you need to know the equation, and while that is true, that's certainly far from all the truth. To effectively solve a problem, you need to know a lot more than just what the equation is. You need to have a conceptual idea of what's going on, in this case, what's going on as a car is accelerating from rest. You also need to pay attention to units, and what we have here is an acceleration from zero to a figure in meters per second, and also kilometers per hour, and also miles per hour, and we're given the time over which this acceleration takes place, or this velocity change takes place. So what I know is a delta V in a T, and what I'm asked to calculate is the acceleration in A. So in the strategy plotting stage of this problem, I'm going to be looking for equations which have A, delta V, and T in it, but I'm also going to be given attention to units, because a good problem solver can often work their way through a problem by paying attention to units. In here, I'm asked to calculate A in meters per second, per second, and also in miles per hour, per second. Divided that way, what you notice is you're going to have to take a velocity change in meters per second, and divide it by time in seconds, but you're also going to calculate it as a velocity change in miles per hour, divided by a time in seconds. Now these numerical values in meters per second, miles per hour, straightforward, they're given right there in the equation, so you simply need to plug it in as delta V, and divide it by the given time, and you've got an answer. And then, one last thing, sometimes before you ever quit a physics problem, it's worthwhile to just kind of stop and look at the numbers, and just say, wow, I want to reflect on it, and here what we've got is a Lamborghini, a race car, and our race car is accelerating at 18 miles per hour per second, meaning that every second that speedometer is going to increase by an amount of 18 miles per hour. That's a pretty incredible car.