Final answer:
The correct answer c) 300 g.For a torque balance problem, if you add 300 g to the sliding carriage at a radius of 15 cm, you should add 300 g to the fixed carriage at the same radius to balance the system.
Step-by-step explanation:
The question is about a torque balance problem in which you need to determine the necessary mass to add to a fixed carriage in a system to balance it. If you add a total mass of 300 grams to the sliding carriage, which is at a radius of 15 cm from the pivot, you need to ensure that the torques on either side of the pivot are equal for the system to be balanced.
In a simple balance, the product of mass and distance (radius) from the pivot on one side should be equal to the product of mass and distance on the other side if we ignore any outside forces or the mass of the lever itself. Since the fixed carriage is also at a radius of 15 cm and assuming it's on the opposite side of the pivot, the mass that should be on the fixed carriage would be the same as that on the sliding carriage to balance it. Therefore, you should have 300 g in the fixed carriage to balance the system, making the correct answer c) 300 g.