Q.

A particle of unit mass undergoes one-dimensional motion such that its velocity varies according to v(x)=βx-2n, where β and n are constants and x is the position of the particle. The acceleration of the particle as a function of x, is given by                  [2015]

1 -2β2x-2n+1  
2 -2nβ2e-4n+1  
3 -2nβ2x-2n-1  
4 -2nβ2x-4n-1  

Ans.

(4)

According to question, velocity of unit mass varies as

v(x)=βx-2n           ...(i),                 dvdx=-2nβx-2n-1              ...(ii)

Acceleration of the particle is given by

a=dvdt=dvdx×dxdt=dvdx×v

Using equation (i) and (ii), we get

a=(-2nβx-2n-1)×(βx-2n)=-2nβ2x-4n-1