Physics

Problem

During a 3-hour trip, a car’s trip computer reports an average speed of

55\text{ mph}

. At exactly

t=2.5\text{ h}

, the speedometer reads

70\text{ mph}

. Which of the following statements best interprets these two pieces of information? a) The car’s speed has been close to

70\text{ mph}

for most of the trip because its instantaneous speed exceeds the average. b) An average speed of

55\text{ mph}

guarantees that the car never exceeded

55\text{ mph}

at any moment. c) Because the instantaneous speed is greater than the overall average, the car must have been traveling at some speed less than

55\text{ mph}

at another time during the trip. d) To balance the

70\text{ mph}

reading at

t=2.5\text{ h}

, the car had to be traveling below

55\text{ mph}

immediately before

t=2.5\text{ h}