Calculate Angular Momentum of 2kg Object at Time t

[vu10758]

A 2kg object has a position vector r = -4t i + 3t^2 j (m). Find its angular momentum relative to the origin as a function of time.

The correct answer is -24t^2 k (kgm^2/s).

I know that L = r*p and p is mv

so I differentiate r to get v

v = -4 i + 6t j

do I just multiply 2 and the cross proudct of r and v? I don't know what to do because of the t in the equation for vector r.

 

[OlderDan]

A 2kg object has a position vector r = -4t i + 3t^2 j (m). Find its angular momentum relative to the origin as a function of time.

The correct answer is -24t^2 k (kgm^2/s).

I know that L = r*p and p is mv

so I differentiate r to get v

v = -4 i + 6t j

do I just multiply 2 and the cross proudct of r and v? I don't know what to do because of the t in the equation for vector r.

Just do it. The angular momentum is to be found as a function of time. t will be in the result