Step-by-step explanation:
hello,
a = ( v - u ) / t
where u is the initial velocity.
and v is the final velocity.
t represents time,
and a represents acceleration.
in this case,
a = 1.4 m/s²
u = 6 m/s
v = 13 m/s
hence,
1.4 = (13 - 6)/t
1.4t = 7
t = 7/1.4
t = 5 s
thank you!