This depends on the context in which work is being defined. In physics, work is generally considered to be positive if it is done on an object, meaning that energy is being transferred to the object. On the other hand, work is considered to be negative if it is done by an object, meaning that energy is being transferred away from the object.
Yes, work can be both positive and negative in the same scenario. For example, if a force is applied to an object and the object moves in the same direction as the force, the work done is considered to be positive. However, if the object moves in the opposite direction of the force, the work done is considered to be negative.
To calculate work as positive or negative, you need to consider the direction of the force and the direction of the displacement. If the force and displacement are in the same direction, the work is positive. If the force and displacement are in opposite directions, the work is negative. You can use the formula W = Fd cosθ, where F is the force, d is the displacement, and θ is the angle between the force and displacement vectors.
The difference between work done on an object and work done by an object is based on the direction of the force and displacement. When work is done on an object, the force is applied on the object and the displacement is in the same direction as the force. When work is done by an object, the force is applied by the object and the displacement is in the opposite direction of the force.
Yes, work can be zero. This occurs when either the force or the displacement is zero, or when the force and displacement are perpendicular to each other. In these cases, there is no work done on or by the object, so the work is considered to be zero.