Three particles `A,B` and `C` and situated at the vertices of an equilateral triangle `ABC` of side of length `l` at time `t=0`,Each of the particles move with constant speed `u`. A always has its velocity along `AB, B` along `BC` and `C` along `CA`.

Three particles A, B and C are situated at the vertices of an equilateral triangle ABC of side d at time t=0. Each of the particles moves with constant speed v. A always has its velocity along AB, B along BC and C along CA. At what time will the particles meet each other?

Three particles A, B and C are situated at the vertices of an equilateral triangle ABC of side d at time t=0. Each of the particles moves with constant speed v. A always has its velocity along AB, B along BC and C along CA. At what time will the particles meet each other?

Three particles A, B and C are situated at the vertices of an equilateral triangle ABC of side d at time t=0. Each of the particles moves with constant speed v. A always has its velocity along AB, B along BC and C along CA. At what time will the particles meet each other?

Three particles A, B and C are situated at the vertices of an equilateral triangle ABC of side d at time t=0. Each of the particles moves with constant speed v. A always has its velocity along AB, B along BC and C along CA. At what time will the particles meet each other?

Four particles A, B, C and D are situated at the corner of a square ABCD of side a at t-0. Each of particles moves with constant speed (v). A always has its velocity along AB, B along BC, C along CD~ and D along DA . At what time will these particles meet each other ?

Four particles A, B, C and D are situated at the cornerst of a square ABCD of side a at t-0 . Each of particles moves with constant speed (v). A always has its velocity along AB, B along BC, C along CB~ and D along DA . At what time will these particles meet each other ?

Three boys A,B and C are situated at the vertices of an equilateral triangle of side d at t=0. Each of the boys moves with constant speed v. A always moves towards C and C towards A, At what time and where they meet each other?

Three boys A,B and C are situated at the vertices of an equilateral triangle of side d at t=0. Each of the boys moves with constant speed v. A always moves towards C and C towards A, At what time and where they meet each other?