# Inelastic collision problem - What is the velocity?

• watsup91749
In summary, two equal masses traveling in opposite directions at equal speeds will collide in a perfectly inelastic collision, resulting in their velocities being zero. This is because in an inelastic collision, the objects stick together and the total momentum is conserved. In contrast, in a perfectly elastic collision, the objects bounce back at the same speed and the total kinetic energy is conserved. A collision between elastic and inelastic would likely result in some loss of energy, but the objects may still separate after the collision.
watsup91749

## Homework Statement

2 equal masses travel in opposite directions at equal speeds. They collide in a perfectly (inelastic) collision. Just after the collision their velocities are:
A)Zero
B)equal to their original velocities
C)equal in magnitude but opposite in direction of their original velocities
D)less in magnitude and in the same direction as their original velocities
E)less in magnitude and opposite in direction as their original velocities

p=mv
f=ma
k=.5mv^2

## The Attempt at a Solution

I believe that the answer is zero, because if they collide with equal mass, and equal velocity, which means they have the same momentum, then they must stop each other, an inelastic collision is where they stick to each other, so then it must be zero.

I have 2 other questions just like this, expect one asks about a "perfectly elastic colllison" and another about a "collision that is between elastic and inelastic" ( i have no idea what that means..).

An elastic collision is a "perfect scenario collision", so they must hit each other and bounce back at the same speed...so it would be B for that one?

Thanks for taking time to read this long post, and please inform me if my logic isn't right..

1, Correct
Perfectly elastic means no energy is lost.
Inelastic collision doesn't necessarily mean they stick - it means that energy is lost (eg to heat)

Well, it says "perfect inelastic collision" so I am assuming they stick,thats what my books says.
So, then for the inelastic collision the answer is A, but for elastic collisions the answer is B?
Does anyone know what the "collision between elastic and inelastic" means and can help me figure it out?

## What is an inelastic collision?

An inelastic collision is a type of collision where the kinetic energy of the system is not conserved. In other words, the total kinetic energy before the collision is not equal to the total kinetic energy after the collision.

## What is the difference between elastic and inelastic collisions?

In an elastic collision, the total kinetic energy is conserved, meaning the total kinetic energy before and after the collision is equal. In an inelastic collision, the total kinetic energy is not conserved and some of the kinetic energy is converted to other forms, such as heat or sound.

## How is velocity calculated in an inelastic collision?

The velocity after an inelastic collision can be calculated using the conservation of momentum principle, where the total momentum before the collision is equal to the total momentum after the collision. This can be represented by the equation m1v1 + m2v2 = (m1 + m2)v, where m1 and m2 are the masses of the objects, v1 and v2 are the initial velocities, and v is the final velocity.

## What factors can affect the velocity in an inelastic collision?

The velocity in an inelastic collision can be affected by the masses and velocities of the objects involved, as well as the type of collision. For example, a head-on collision will result in a different final velocity compared to a rear-end collision. Friction and external forces can also affect the velocity in an inelastic collision.

## Can the velocity in an inelastic collision ever be negative?

Yes, the velocity in an inelastic collision can be negative if the objects involved are traveling in opposite directions and have different masses. In this case, the final velocity will be negative, indicating that the objects are moving in opposite directions after the collision.

• Introductory Physics Homework Help
Replies
9
Views
1K
• Introductory Physics Homework Help
Replies
10
Views
1K
• Introductory Physics Homework Help
Replies
16
Views
2K
• Introductory Physics Homework Help
Replies
7
Views
3K
• Introductory Physics Homework Help
Replies
2
Views
1K
• Introductory Physics Homework Help
Replies
2
Views
2K
• Introductory Physics Homework Help
Replies
4
Views
1K
• Introductory Physics Homework Help
Replies
21
Views
2K
• Introductory Physics Homework Help
Replies
22
Views
3K
• Introductory Physics Homework Help
Replies
11
Views
1K