Final answer:
The statement that a leftward force does negative work on an object moving right is true because work is calculated as the product of the force and displacement in the direction of the force; here they are opposite.
Step-by-step explanation:
The student's question pertains to the concept of work in physics and how it is defined when forces act on an object. When an object is moving in one direction and a force acts upon it in the opposite direction, the work done by that force is considered negative. This relates directly to the definition of work, which is a product of the force applied to an object and the displacement of the object in the direction of the force. If the displacement is in the opposite direction to the force, the work done is negative because the angle between the force and the displacement is 180 degrees, and the cosine of 180 degrees is -1. Therefore, the statement that a leftward force doing negative work on an object moving to the right is True.