Recent content by physicsxlove

Omg. I am so dumb. I just calculated the second derivative and then used to sit brooding over what to do next without plugging the value of l from equation 1. I am feeling embarrassed. Anyway,,, thank you. I got it. Better late than never.

Here i have attached the photo graph of that page.

I am self studying Kleppner and Kolenkow's an Introduction to mechanics. But i have one doubt about how they got into the equation no 3 of the example problem 9.3 in Central Force Motion. Please clarify my doubt.