The angular position of a free wheel is given by \(\theta =4t-3{{t}^{2}}+{{t}^{3}}\) where \(\theta \) is in radians and t in seconds. The average angular acceleration of the wheel for the time interval t= 2 s to t= 4 s will be
1
10 rad/s2
2
18 rad/s2
3
15 rad/s2
4
12 rad/s2