You are building a Rube Goldberg device. A 3 kg ball rolls down an incline and through a loop with radius 5m. How high does the initial incline have to be for the ball to stay attached to the track at all times?

Respuesta :

Given data

mass of the ball = 3 kg ;  

loop radius (r) = 5m,

Determine the height  to stay the ball on an incline track (h) = ?

We know that from loop the loop concept,

                                        h = (5r/2)

                                        Where, r = radius of the loop,

Derivation of equation for h;

           From Newtons II law F = m .a  or  F = m. g

           Net force acting at the top of the loop,

                                 Fr = F + m.a  

                                          since  two forces acting down at the top

                         m. V²/r = m. g          

                                        where  

                                         m. V²/r  = net force  

                                         since a = g(ball rolls due to gravitational force)

                              V²/r = g

                               V = √(g.r)   ----------------- (i)

The kinetic energy is  acting at the top of the loop which is equal to potential energy (from energy conservation)

                        m.g (2r) + 1/2 m.g.r = m.g.h

                                   2r + 1/2 .r = h

                      Further simplification of above equation

                                   h = 5r/2

                                             ----------- end of equation derivation


So, to determine the height of incline, such that ball should  stay attached to the track is given by

                                 h = 5r/2

                                     = (5 × 5)/2

                                     = 12.5 m

            The ball to stay attached to the track, the height of incline should be 12.5 m.



           

                           

                         

                                       


                                                                         

                           

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