Please help me answer this!

Question

Charlotte is driving at 70.8 miles/hour and receives a text message. She looks down at her phone and takes her eyes off the road for 4.80 seconds. How far has Charlotte traveled in feet during this time?

Answer 1

First, the speed Charlotte is traveling must be convrted from miles per hour into feet per second; then this speed must be used to calculate the distance in feet she travels in 4.8 seconds.

When converting units use dimensional analysis where the units will cancel as the conversion is done. the miles cancel on top and bottom; the hours on bottom and top cancel ; and leave the feet per seconds.

70.8 miles/ hour x 5280 feet/ mile x 1 hour/ 3600 seconds = 103.84 feet/ sec

4.8 seconds x 103.84 feet/second = 498.432 ft = 500 feet rounded due to significant figures in the question. Only two significant figures in the questions - 4.8 seconds means only 2 significant figures in the answer.

Just to make you think this is 1 2/3 football fields. A very long distance for Charlotte to take her eyes and mind off of the road!