Question

0515
A particle is projected
along a horizontal field
whose coefficient of
friction varies as M=4/r^2
where r is the distance
from the origin in metres
and A is a positive
constant. The initial
distance of the particle is
1m from the origin and its
velocity is radially
outwards. The minimum
initial velocity at this point
so that particle never
stops is​

Answer 1

Step-by-step explanation:

Work done against friction is equivalent to the kinetic energy of the body

2

1

mv

2

=

1

∫

∞

μmgdr

2

v

2

=

1

∫

∞

r

2

A

gdx

2

v

2

=−Ag[

r

1

]

1

∞

v

2

=2Ag

v=

2Ag