In the formula $W = Fs \cos θ$, the angle between force and displacement (θ) is equal to 90°, the net work done will be:

Zero

The correct answer is option 4. Zero.

In the formula for work \( W = F \cdot s \cdot \cos \theta \), the angle \( \theta \) represents the angle between the force vector \( F \) and the displacement vector \( s \).

When the angle \( \theta \) is 90° (perpendicular), it means that the force is acting perpendicular to the direction of displacement. In this scenario, the force does not contribute to the displacement; it merely acts in a direction perpendicular to it.

Now, the cosine of 90° is 0 (\( \cos 90° = 0 \)). When you multiply any value by 0, the result is 0. So, if \( \theta = 90° \), then \( \cos \theta = 0 \), and the entire term \( F \cdot s \cdot \cos \theta \) becomes 0.

Therefore, when the angle between the force and displacement vectors is 90°, the net work done (\( W \)) is 0. This means that no energy is transferred in the direction of motion, and hence, the work done is zero. The force might be exerting some influence, but it is not contributing to the displacement in the direction of the force.