Conservation of Momentum in a Fishy Encounter

[amynjax23]

Homework Statement

A 5kg fish is swimming at 1m/s swallows an absent minded fish swimming 1kg fish at rest. (a) Show that the speed of the larger fish after lunch is -5m/s. What would be its speed if the smaller fish was traveling toward it at 4m/s

Homework Equations

momentum=mv?

The Attempt at a Solution

I don't know what to do...sorry

 

[PhanthomJay]

You can use conservation of momentum, but first you need to correct your problem statement '..fish swimming 1kg fish at rest..'