Worked Examples-Calculation Part 1 - Equilibrium

Considered Formula

$$M = F \times d$$ $$\quad\text {Where}~~M \to Moment ~of Force,\quad F \to Force \\\quad d \to Perpendicular~distance$$

Example 1

A line of action of a force of 90 N acts at a perpendicular distance of 2.5 m, from a point. Find the moment of the force

Solution

Data given

Force (F) = 90 N

Perpendicular distance (d) = 2.5 m

Moment of force (M) =?

$$~~~~~~~~~~~~~~~~~~~~~~~~~~~~M = F \times d$$ $$~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ = 90 \times 2.5$$ $$~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ = 225~Nm$$

The moment of the force = 225 Nm

Example 2

A man applied a force of 200 N acts at a perpendicular distance of 40 cm, from hinges to open a door. Find the moment of the force

Solution

Data given

Force (F) = 200 N

$$\text {Perpendicular distance (d)}= 40 cm = \Biggl( \frac {40}{100}\Biggr)~m = 0.4 m$$

Moment of force (M) =?

$$~~~~~~~~~~~~~~~~~~~~~~~~~~~~M = F \times d$$ $$~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ = 200 \times 0.4$$ $$~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ = 80~Nm$$

The moment of the force = 80 Nm