lami's rule

If three forces P, Q, R acting on a particle keep it in equilibrium then, P + Q + R =

The resultant of two equal forces will bisect the angle between them.

• True

• False

The greatest resultant of two forces of magnitudes P and Q has magnitude

• P + Q

• P - Q

• 0

• R

If the resultant force R is least then, the angle between the two forces P and Q will be

• $\pi$

• $\pi$ / 2

• $\pi$ / 4

• 0

The weight of the body acts

• Vertically

• Vertically Upwards

• Vertically Downwards

• Horizontally

The resultant of two unlike parallel forces P and Q is

• P + Q

• P - Q

• R

• 0

If the  forces are equal at an angle 

 $\alpha$  then the angle made by the resultant with these forces is

•  $\alpha$  / 2

•  $\alpha$  / 3

• 3 $\alpha$  

• 2 $\alpha$  

If the forces are at right angles, then the parallelogram made by the forces become

• Square

• Rectangle

• Rhombus

• Triangle

By Lami's theorem, P/ sin( Q , R) = Q / sin( R , P) =

• R

• R / sin ( P , Q)

• P / Q

• P / R

The direction of the resultant of the forces P and Q is given by 

 $\tan\ \phi$ =  

•  $\frac{Q\sin\alpha}{P\ +\ Q\cos\alpha}$  

•  $\frac{Q\cos\alpha}{P\ +\ Q\sin\alpha}$  

•  $\frac{P\sin\alpha}{Q\ +\ P\sin\alpha}$  

• None of the above