A particle moves in such a way that its displacement from a reference point at any instant is given by s=7t2+3 where s is in metres and t in seconds. Find its average velocity v- in the time interval between 3 s and 4 s and its instantaneous velocity v at 2 s.
Select one:
v-=67 ms-1; v=34 ms-1
v-=28 ms-1; v=49 ms-1
v-=49 ms-1; v=28 ms-1
v-=34 ms-1; v=67 ms-1
