The following are speeds and headings displayed on a GPS receiver. (Heading gives the direction of motion based on north 5 0°, east 5 90°, south 5 180°, etc.) In each case, indicate whether the receiver was accelerating during the time between the displays and, if it was, describe in what way the receiver was accelerating.
(a) Initially: 60 mph, 70°; 5 seconds later: 50 mph, 70°.
(b) Initially: 50 mph, 70°; 5 seconds later: 70 mph, 70°.
(c) Initially: 60 mph, 70°; 5 seconds later: 60 mph, 90°.