A maintenance hatch extends horizontally to the right of a hinge along its left-hand edge. The table gives the vertical downward forces acting on the hatch.
| Force | Magnitude | Distance from the hinge |
|---|---|---|
| weight of the hatch | 180 N | 0.60 m |
| weight of an equipment case | 240 N | 0.90 m |
A further force acts vertically at a distance of 1.20 m from the hinge. This force may act upwards or downwards.
Calculate the magnitude of the further force needed to keep the hatch in rotational equilibrium and state its direction.
The force calculated in part (a) is kept the same in both magnitude and direction but is applied 0.80 m from the hinge instead. Explain what happens to the hatch when it is released.