The position vector of a particle is given by r⃗ = √3 t² î + √2 t ĵ + √5 k̂. Which one of the following statements is correct?

Differentiating r⃗ with respect to time gives velocity v⃗ = 2√3 t î + √2 ĵ. Differentiating again gives acceleration a⃗ = 2√3 î (a constant vector in x-direction). The momentum p⃗ = m v⃗ has components in both î and ĵ directions, while the force F⃗ = m a⃗ has only an î component. Therefore the force is neither parallel nor perpendicular to the momentum (their dot product is non-zero, and they are not scalar multiples of each other). Hence the force is not parallel to the instantaneous momentum.