Acceleration can increase due to several factors. The primary factor is the application of a force. According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. So, if the force acting on an object increases while its mass remains constant, the acceleration will increase.
Additionally, acceleration can also increase if the mass of the object decreases while the force acting on it remains constant. This is evident in situations where an object loses mass, such as a rocket expelling fuel during propulsion. As the mass decreases, the same force applied to a smaller mass results in a higher acceleration.
It's important to note that acceleration is a vector quantity, meaning it has both magnitude and direction. So, changes in acceleration can also occur when the direction of the force changes or when multiple forces act on an object simultaneously. In such cases, the acceleration can increase or decrease depending on the resultant force and its direction.
In summary, acceleration can increase when the force acting on an object increases, or when the mass of the object decreases, or when there are changes in the direction or combination of forces acting on the object.