For a moving object, the force acting on the object varies directly with the object's acceleration. When a force of 21 N acts on a certain object, the acceleration of the object is 7 m/s^2 . If the acceleration of the object becomes 9 m/s^2, what is the force?
___N
F = k * a
Using the first scenario where F = 21 N and a = 7 m/s^2:
21 = k * 7
k = 21 / 7
k = 3
Now using the second scenario where a = 9 m/s^2:
F = 3 * 9
F = 27
Therefore, the force acting on the object when the acceleration is 9 m/s^2 is 27 N.