We know thatτ=r×FGiven:-r=−0.5i^m F=−mgj^​ The torque becomes:​τ=0.5(−i^)×mg(−j^​)τ=0.5mgk[∵i^×j^​=k]​ No, there will be no angular acceleration on the particle due to the torque. Angular acceleration is given by α=Iτ​. As the particle here moves in a straight line, the centre of rotation lies at a distance infinity (r=∞) ; so, moment of inertia( I= mr2 ) of the particle is infinity.∴α=0