Answer Happy

The answer of radius is 0.274 micrometer.
Please Sketch the inital trajectory of the grain and the
asteroid orbit!!!!!
a -3 A type of spherical dust grain, some distance from the Sun, has a reflectivity of 0.5 and density of 3200 kg m-3. Calculate the grain radius for which the forces on the grain of solar gravity and solar radiation pressure exactly balance. A grain of this radius and type is lost from a small asteroid that is in a circular orbit around the Sun. The grain has an initial velocity in the direction of motion of the asteroid. Sketch the inital trajectory of the grain and the asteroid orbit.