Chapter 6, Problem 74GP

(a)

To determine

The reason due to which a scale shows a non-zero reading in the first experiment, when the blade of the helicopter is not touching the scale. Given that Martha has a remote controlled toy helicopter which she uses to investigate the mechanism of a helicopter, by fixing a long stick and holding it directly above the plate of a long scale without touching it and allowing the blade to rotate with maximum speed. The scale reading shows zero before touching the helicopter and shows 54g when the blades are rotating.

(b)

To determine

The reason due to which the scale shows an increased reading in the second experiment after the blades start rotating and the reason because of which Martha expected the readings to decrease, when in the second experiment she fixes the helicopter legs to the scale plate with scotch tape and lets the blade rotate with maximum speed. The scale shows the mass of the helicopter as 123g before blades are rotating and 134g after the blades start to rotate.