At time t = 0 a 2 kg paticle has position vector `vec (r ) = (4 hat(i) - 2 hat(j))` relative to the origin Its velocity is given by `v=2t^2` (m/s) for t≥0. The torque acting on the particle about the origin at at t = 2s , is

Options

A. `32 hat(k) ` N-m
B. `-16 hat(k) N-m `
C. `16 hat(k) `N-m
D. `12 hat(k) ` N-m

Answer

A

Explanation

`bar(tau) = vec(r) xx vec(F) " where" bar(F) = mbar(a) = m ((dbar(v))/(dt))`