Reference Frame

The reference frame, in which the centre of inertia of a given system of particles is at rest, translates with a velocity V relative to an inertial reference frame K. The mass of the system of particles equals m, and the total energy of the system in the frame of the centre of inertia is equal to overset~E . Find the total energy E of this system of particles in the reference frame K.

STATEMENT-1 : Acceleration of a particle in a reference frame may be non- zero , even if net external force acting on the particle is zero. and STATEMENT : 2 In a non- - inertial reference frame, Newton's second law is not valid.

STATEMENT-1 : Acceleration of a particle in a reference frame may be non- zero , even if net external force acting on the particle is zero. and STATEMENT : 2 In a non- - inertial reference frame, Newton's second law is not valid.

A rod flies with constant velocity past a mark which is stationary in the reference frame K. In the frame K it takes Deltat=20ns for the rod to fly past the mark. In the reference frame fixed to the rod the mark moves past the rod of Deltat^'=25ns . Find the proper length of rod.