Question

A stick of 5cm contains two parallel forces P&Q as the picture.the resultant force is 50N which is 2cm far from P force on the stick.what is the value of P&Q?

Answer 1

P = 30 N and Q = 20 N

Explanation:

We need to use methods to generate two equations as there are two unknowns.

Step 1: Resolve forces vertically
`P + Q = R = 50" N"` ①

Step 2: Take moments about one point
The moments about any point are equal to the moment produced by the resultant about the same point.

Take moments about P to eliminate it from the equation (since the moment due to a force with zero perpendicular distance is zero).
`M_P = Q × 5 = 50 × 2 ⇒ Q = 100/5 = 20" N"`

Now substitute the value of Q into equation ① .
`P = 50 - 20 = 30" N"`