As we know that centripetal acceleration is given as
[tex]a_c = \frac{v^2}{R}[/tex]
here we know that
linear speed = 35 m/s
here radius of path is same as length of arm
R = 0.7 m
now from above above formula we have
[tex]a_c = \frac{35^2}{0.7}[/tex]
[tex]a_c = 1750 m/s^2[/tex]
so acceleration is 1750 m/s/s