Answer
$v=11.54m/s$
Work Step by Step
1) Find the centripetal acceleration $a_c$ of the satellite
Since the centripetal force of a satellite is the same as its gravitational force, the centripetal acceleration is similar to the gravitational acceleration: $a_c=g$
To find $g$, we have the formula $$g=G\frac{M_E}{r^2}$$
We have $G=6.67\times10^{-11}Nm^2/kg^2$, $M_E=5.98\times10^{24}kg$ and radius $r$ is given to be $6.7\times10^6m$. Therefore, $$a_c=g=8.885m/s^2$$
2) The plane has the same $a_c=8.885m/s^2$ and its radius of flying path $r=15m$. Its speed needs to be $$v^2=a_cr=133.275m^2/s^2$$ $$v=11.54m/s$$
