Q.

Let L and P represent the angular momentum and linear momentum respectively of a particle of mass 'm' having position vector r=a(i^ cos ωt+j^ sin ωt). The direction of force is         [2025]

1 Opposite to the direction of r  
2 Opposite to the direction of L  
3 Opposite to the direction of P  
4 Opposite to the direction of L×P  

Ans.

(1)

r=a cos ωti^+a sin ωtj^

v=drdt=aω sin ωti^+aω cos ωtj^

a=dvdt=aω2cos ωti^aω2sin ωtj^

a=ω2(a cos ωti^+a sin ωtj^)=ω2r

a is antiparallel to r

Hence, F is opposite to the direction of r