IIT JEE , AIEEE Forum - Physics , Mechanics

science4u

Three equal forces of 20N each act on a particle.The angle btwn any two successive forces is thetha.What is the resultant?

please explain with diagram and step by step.

savvej

ans is 40N.

let a,b,c be thre forces.the angle btwn any two succesive vectors is theta.therefore theta+theta+theta =360
=> theta =120
since u can use triangle rule only if the tails of vectors coincide by translating the vector you can the angle betwn the vector to be 60⁰ .The resultant by using (a² + b² +2abcostheta )^1/2 is 1200^1/2 and since the vectors are equal the resultant will bisect the angle and make an angle 30⁰.the angle btwn the resultant and the third vector will be thus 120-30=90 .therefore angain the resultant will be (1200 + 400+0)^1/2 =40N

thnk you.

krishna.gopal

It will be zero. Because three equall forces acting at 120 degree to each other will have zero resultant

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