Answer:
the acceleration will be 10 m/s^2
Step-by-step explanation:
the force applied to an object and the acceleration of the object are directly proportional, as Newton's second law states:

where
F is the net force applied to the object
m is the object's mass
a is the object's acceleration
in the first example, a force F=45 N is applied to the object, giving it an acceleration of a=5 m/s^2. Therefore, the mass of the object is

In the second example, the force is doubled, so it will be F=90 N. The mass is still m=9 kg, so the acceleration will be
