Final answer:
The magnitude of the force is given by the formula F = √(a² + b²), where a is the x-component of the force and b is the y-component of the force. In this case, a = a and b = 10. Therefore, the magnitude of the force is √(a² + 10²), which corresponds to option C.
Step-by-step explanation:
The magnitude of force is given by the formula F = √(a² + b²), where a is the x-component of the force and b is the y-component of the force. In this case, a = a and b = 10. Therefore, the magnitude of the force is √(a² + 10²), which corresponds to option C. So, the correct answer is C. sqrt(a² + 10²).