Question

Two hockey pucks, labeled A and B, are initially at rest on a smooth ice surface and are separated by a distance of 18.0 . Simultaneously, each puck is given a quick push, and they begin to slide directly toward each other. Puck A moves with a speed of 1.30 , and puck B moves with a speed of 1.70 .

What is the distance covered by puck A by the time the two pucks collide?

Answer 1

The pucks are traveling towards one another, so their relative velocity becomes:
1.3 + 1.7 = 3 m/s
The time it will take for them to collide:
18/3 = 6 seconds

In this time, the distance each puck will cover:
Da = 1.3 x 6
= 7.8 m

Db = 1.7 x 6
= 10.2 m