If an object is facing an opposing motion, its acceleration would depend on the net force acting on it and its mass. According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. Mathematically, this can be expressed as:
a = F_net / m
where: a is the acceleration of the object, F_net is the net force acting on the object, and m is the mass of the object.
If the opposing force acting on the object is known, the net force can be calculated by subtracting the opposing force from the applied force. The direction of the opposing force would determine the sign of the net force and, subsequently, the direction of acceleration.
It's important to note that acceleration is a vector quantity and must include both magnitude and direction. Therefore, the term "opposing motion" needs further clarification to determine the precise direction of acceleration.