# Elastic and inelastic collisions

#### MBBphys

Gold Member
1. Homework Statement
In a closed system, in an inelastic collision, momentum and total energy is conserved, but total kinetic energy is not.
But how is this possible? If we have a change in total kinetic energy, we have a change in velocity, and so we must have a change in momentum as:
momentum=mass*velocity
So I am really confused!
Thanks :)

2. Homework Equations
n/a

3. The Attempt at a Solution
n/a

Related Introductory Physics Homework Help News on Phys.org

#### TSny

Homework Helper
Gold Member
Keep in mind that kinetic energy is a scalar quantity and momentum is a vector quantity.

Think about the example of two equal masses moving toward each other with equal speeds and the two masses stick together and come to rest after they collide.

### Want to reply to this thread?

"Elastic and inelastic collisions"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving