Question

how to know which equation of motion to use in which question​

Answer 1

It is quite easy to figure out which equation of motion to use once we get the hang of it. Here are a few tips:

• Analyse the data: Before jumping to a conclusion, try to carefully examine the data given. Sometimes, we may not get the answer just by using one formula, and we may need to use a second formula to derive the answer.

• Know the formulae: To correctly use the formulae, we must know them like the back of our hand. They are:

1. v = u + at
2. s = ut + 1/2at²
3. v² = u² + 2as

    We also might need to use F = ma to derive the acceleration sometimes.

       

• Know which one to use: For example, if we have been given the final velocity (v), initial velocity (u) and time (t), and we have to find acceleration (a), we will use the first formula of motion (v = u + at). Similarly, if we have been given the initial velocity (u), time (t) and acceleration (a), and we have to find the displacement of the body (s), we will use the second formula of motion (s = ut + 1/2at²), and so on.

• Get practice: As we all know, practice makes a man perfect. Doing just a few sums a day will do you wonders. I recommend buying a practice book to get in a lot of practice.

I hope it helps!