Answer: The force on an object is directly proportional to its acceleration, which means that if the force is increased, the acceleration will also increase, and if the force is decreased, the acceleration will decrease. This can be expressed mathematically as:
F = k * a
where F is the force, a is the acceleration, and k is a constant of proportionality.
We can use the given information to find the value of k:
30 N = k * 10 m/s^2
k = 3 N*s^2/m
Now we can use this value of k to find the acceleration when the force is 9 N:
9 N = 3 Ns^2/m * a
a = 3 Ns^2/m / 9 N
a = 1/3 m/s^2
Therefore, the acceleration of the object when the force is 9 N is 1/3 m/s^2.