Mass of the paper cup = 0.025 kg
Rate of acceleration of the cup due to force of wind = 5 m/s^2
We already know that
Force = Mass * Acceleration
So Force exerted by the wind on the cup = 0.025 * 5 kg m/s^2
= 0.125 Newton
So the force exerted by the wind on the paper cup is 0.125 newton. I hope this is the answer that you wanted and the process of doing such problems is clear to you.