What is the First Derivative of Kinetic Energy?

[Jason03]

I had a question on the first derivative of Kinetic Energy...This a problem from the FE exam...

Now the solution is = mva...which turns out to be power...im just trying to understand how they came up with that...

so KE = 1/2 mv^2


im asuming they are using the general power rule so v^2 would be 2v dv/dt where dv/dt is acceleration...

the m is where I am confused...the derivative of m would just be 1...but why not dm/dt as well...obviously it wouldn't make sense because the mass wouldn't change with time...but i guess I am rusty on the power rule...

 

[rock.freak667]

I had a question on the first derivative of Kinetic Energy...This a problem from the FE exam...

Now the solution is = mva...which turns out to be power...im just trying to understand how they came up with that...

so KE = 1/2 mv^2


im asuming they are using the general power rule so v^2 would be 2v dv/dt where dv/dt is acceleration...

the m is where I am confused...the derivative of m would just be 1...but why not dm/dt as well...obviously it wouldn't make sense because the mass wouldn't change with time...but i guess I am rusty on the power rule...

m is a constant, v is the only thing changing with time, that's why you differentiate the v² with respect to t

 

[Jason03]

perfect!...that makes sense...I thought it was something to do with mass not changing...but i forgot i was taking the derivative with respect ot time...

thank you