Final answer:
The mass of the block on the left is 4.0 kg, which is used to determine the system's acceleration by applying Newton's second law and considering various forces such as gravity and friction.
Step-by-step explanation:
The mass of the block on the left, referred to as m1, is 4.0 kg. This information is given in the second statement. In physics problems like this, the mass is an essential component to solve for other variables such as acceleration, force, and tension. Using the provided coefficient of friction and the incline angle, one can calculate the net force and subsequently the acceleration of the system. The process typically involves applying Newton's second law, which states that the force equals mass times acceleration (F=ma), and factoring in the forces of gravity, normal force, friction, and any applied forces.