When is mechanical work zero?

Mechanical work A is determined by the formula: A = F * S * cosα, where F is the force that acts on the body, S is the movement of the body under the action of the force, ∠α is the angle between the force F and the displacement S. Mechanical work is equal to 0 when one of the factors is zero.
1. Mechanical work A = 0, when the force F does not act on the body.
2. Mechanical work A = 0, when the movement of the body S = 0.
Example: a body lies on a table, gravity acts on it, but the body does not move. S = 0, A = 0.
The spring was stretched and kept in a stretched state: the movement of the spring S = 0, A = 0.
The work of the electrostatic force in a closed trajectory, the charged particle returns to its initial position, S = 0, A = 0.
3. Mechanical work A = 0, when cosα = 0, ∠α = 90.
Example: a sled is pulled along a horizontal road. The work of the force of gravity is A = 0. The force of gravity is directed vertically downward, and the sled moves horizontally. ∠α = 90, cos90 = 0, A = 0.