A theoretical investigation into (i) the motion of a spherical particle in a gas flow with a simple shear and (ii) the motion of a spherical particle in a gas flow over a wavy wall is described. The lift force on the particle due to the rate of shear of the gas is taken into consideration. Analytical solutions for the particle motion are obtained in both cases under the conditions that the gas properties are not affected by the presence of particles and also the gas is inviscid except for its interaction with solid particles. Sample calculations are carried out for a few typical conditions.