Answer
See below.
Work Step by Step
There is a maximum force of static friction that will act on an object. Friction will resist motion until this force is greater than the maximum force of static friction. For example, the maximum force of static friction is given by $F_{s,max}=\mu_smg$ Using assumed values of $\mu_s=0.5$, $m=10kg$, and $g=10m/s^2$ would give a maximum force of static friction of $F_{s,max}=50N$. If the net force on the strawberries is $35N$, it is less than the force of maximum static friction, so the friction will resist motion. However, once the force becomes a value greater than 50N, for example 70N, the frictional force can only exert up to 50N of force, so the strawberries would now have a net force of 20N and have an acceleration.