Answer
Please see the work below.
Work Step by Step
We know that
$v=\frac{9000+100}{35\times 60}$
$v=4.333\frac{m}{s}$
The leader arrives at the following time
$t=\frac{900}{4.333}=208s$
Now we can determine acceleration as follows
$x=x_{\circ}+v_{\circ}t+\frac{1}{2}at^2$
We plug in the known values to obtain:
$1000=0+4.333(208)+\frac{1}{2}(a)(208)^2$
$a=0.0045\frac{m}{s^2}$
