Oh.. I see. I did not now that d(x ⋅ y)/dt = x' ⋅ y + x ⋅ y'
Knowing this, going right from left is easy, but I guess going left to right needs some practice to spot!
Thank you both peroK and Jedishrfu!
In a book I was reading, it says
F=mv'=P'
so dot producting on both sides with v
F ⋅ v = mv ⋅ dv/dt = 1/2 m d(v2)/dt = d(1/2 m v^2)/dtI really don't get how v ⋅ dv/dt = 1/2 d(v2)/dt.
I have seen few threads and they say it's about product rule, but they don't really explain in detail.
Could...