Final answer:
Work is done in a situation where there is a force applied in the direction of motion with displacement, such as when an object is moving at a constant speed with an applied force in that direction. Therefore the correct option is 2) When an object is moving with a constant speed.
Step-by-step explanation:
When considering the question of in which situations is work being done at a constant velocity, it's important to understand the concept of work in physics. Work is defined as the process of a force causing the displacement of an object. For work to be done, there must be a displacement and a component of the force must act in the direction of the displacement. Given the options, work is being done in situation 2) When an object is moving with a constant speed if there is a force applied in the direction of the motion. Although velocity is constant, the presence of an applied force along the direction of motion results in work. In contrast Therefore, the key factor for work to be done is that there must be force and displacement in the same direction, which can be the case even at constant velocity.