Final answer:
The tension in the cable supporting a lift moving upwards is twice the tension when the lift moves downwards. The acceleration of the lift is g/2.
Step-by-step explanation:
To determine the tension in the cable supporting a lift, we need to consider the forces acting on the lift. When the lift moves upwards, the tension in the cable is greater than when it moves downwards. This is because the net force acting on the lift is equal to the mass of the lift multiplied by its acceleration.
When the lift moves upwards, the tension in the cable is the sum of the weight of the lift and the net force applied to it. Since the tension is twice as large as when the lift moves downwards, the net force is also twice as large. Therefore, the acceleration of the lift is half the acceleration due to gravity (g).
Therefore, the correct answer is C. g/2.