6 A particle, of mass 5 kg , moves on a circular path so that at time \(t\) seconds it has position vector \(\mathbf { r }\) metres, where
$$\mathbf { r } = ( 2 \sin 3 t ) \mathbf { i } + ( 2 \cos 3 t ) \mathbf { j }$$
6
- Prove that the velocity of the particle is perpendicular to its position vector.
6 - Prove that the magnitude of the resultant force on the particle is constant.