A) 7 m/s
B) 9 m/s
C) 13 m/s
D) none of these
Correct Answer: B
Solution :
Rate of change of displacement is velocity, i.e., \[v=\frac{dx}{dt}\] \[v=\frac{dx}{dt}=3-8t+3{{t}^{2}}\] Given, \[x=3t-4{{t}^{2}}+{{t}^{3}}\] \[v=\frac{dx}{dt}=3-8t+3{{t}^{2}}\] At \[t=2,\,{{v}_{1}}=3-16+12=-1\] At \[t=4,\,{{v}_{2}}=3-32+48=19\] Average velocity\[=\frac{{{v}_{1}}+{{v}_{2}}}{2}\] \[=\frac{-1+19}{2}=9\,m/s\]You need to login to perform this action.
You will be redirected in
3 sec