In a dramatic lecture demonstration, a physics professor blows hardacross the top of a copper penny that is at rest on a level desk.By doing this at the right speed, he can get the penny toaccelerate vertically, into the airstream, and then deflect it intoa tray, as shown in the figure . Assuming the diameter of a pennyis 2.10 cm and its mass is 2.50 g, what is the minimum air speed needed to lift the penny off the table top? Assume the air under the penny remainsat rest.