Which of the following frequencies falls in the range of rf waves used by commercial radio broadcasting stations?
a. 6,000 hz
b. 6,000,000 hz
c. 60 hz
d. 600,000 hz

In which situation is the acceleration of a car negative? question 5 options: a)the velocity of a car was 75 km/hr over 4 hours. b)the velocity of a car reduced from 50 km/hr over one minute. c)the velocity of a car increased from 40 km.h to 75 km/h over 15 minutes. d)the velocity of a car was 45 km/hr at 2: 00pm and at 4: 00pm its velocity was 85 km/ht.