# Chapter 3 - Kinematics in Two Dimensions; Vectors - Problems: 41

23.1 seconds.

#### Work Step by Step

The relative speed of approach of the two head-on planes is 2(780 km/h) = 1560 km/h. If no action were taken, they would collide in a time of $t = \frac{10.0 km}{1560 km/h} = 0.00641 hours$, which is approximately 23.1 seconds.

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.