Charlotte is driving at 53.5 mi/h and receives a text message. She looks down at her phone and takes her eyes off the road for 3.97s. How far has Charlotte traveled in feet during this time?

Answer 1

Use dimensional analysis with the following conversion factors.

60 s / min; 60 min / hr; 5280 ft / mi

3.97 s x 1 min / 60 s x 1 hr / 60 min x 53.5 mi / hr x 5280 ft / mi = 312 ft (3 sig. figs.)

Breaking this down into the component parts (if you didn't follow the dimensional analysis:

3.97 s x 1 min / 60 s = 0.06617 minutes

0.06617 minutes x 1 hr / 60 min = 0.001103 hours

0.001103 hrs x 53.5 mi / hr = 0.0590 miles

0.0590 mi x 5280 ft / mi = 312 feet