Answer:
V = 0.39 m/s
Explanation:
Given that,
Mass of hockey puck, m = 0.2 kg
Mass of goalie = 40 kg
Speed of hockey puck, v = 80 m/s
We need to find the speed with which the goalie slide on the slide. Let V be the speed. Using the conservation of momentum as follows :

So, the required speed is 0.39 m/s.
Answer:
An object is in motion if it changes position relative to a reference point.
Explanation:
A physical change in something doesn't change what the it is. For example, if you break glass, it will still be glass. In a chemical change where there is a chemical reaction, a new thing is formed and energy is either given off or absorbed. For example, when you burn a log. The carbon in the log is reacting to the oxygen to create ashe and smoke