Foe an arbitrary motion in sparce, which ot the following relations are true :
(a0 ` vec (average ) = 1/2 [ vec v (t_10 + vec v (t_2)]`
(b) ` vec _(average ) = [vec r 9t_2) - vec r (t-1 0 ] // (t_2 -t_10`
(c ) `vec v(t) = vec v (0) + vec a t`
(d) ` vec r 9t) = vec r90) + vec v (0) t + ( 1//2 ) vec a t^2`
(e) ` vec a_(average) =[ vec v( t_2) - vec v (t-2 ) ] // (t_2 -t_1)1
The average stands for average of the wuantity over the time interval ` t_1` and t_2` ].

Explanation

The relations (b) and (e ) are true , others are false because relations (a) , (c ) and (d) hold only uniformly acceleration motion.