# (101)Conservation of linear momentum

• WPCareyDevil
In summary, the conservation of linear momentum states that the momentum of an object before an interaction must equal the momentum after the interaction. In this problem, a man with a mass of 86.7 kg throws a book with a mass of 0.1 kg at a speed of 11.2 m/s on a frictionless ice surface. To find the man's resulting speed, the equation m1v1=m2v2 is used. After solving for the book's momentum and setting it equal to the man's momentum, the correct answer is found to be 0.0129 m/s.
WPCareyDevil
[SOLVED] (101)Conservation of linear momentum

## Homework Statement

A 86.7 kg man is standing on a frictionless ice surface when he throws a 0.1 kg book at 11.2 m/s. With what speed does the man move across the ice as a result?

## Homework Equations

Since the momentum of the thrown book must equal that of the man in the opposite direction, m1v1=m2v2, or so I thought.

## The Attempt at a Solution

I solved for the momentum of the book (.1)(11.2)=1.12 and then set that equal to the man*v

So... 1.12=86.7v, v=.0723

But that's was incorrect. So, no credit on my webassign homework but I would still like to understand how to solve it. Can someone help me out?

When I divide 1.12 by 86.7, I get 0.01291811 ;-)

UGH! you're completely right... I mustve just been to antsy with the ANS key on my calculator... how irritating. But my reasoning is sound I assume?

## 1. What is the law of conservation of linear momentum?

The law of conservation of linear momentum states that the total momentum of a closed system remains constant, regardless of any external forces acting on the system. This means that in the absence of external forces, the total momentum of the objects in the system will not change.

## 2. How does the law of conservation of linear momentum apply to collisions?

In collisions, the total momentum of the objects before and after the collision must be equal. This means that the sum of the momentum of the objects before the collision will be equal to the sum of the momentum of the objects after the collision.

## 3. Can the law of conservation of linear momentum be violated?

No, the law of conservation of linear momentum is a fundamental law of physics and has been extensively tested and proven to hold true in all physical interactions.

## 4. What is the difference between elastic and inelastic collisions in terms of conservation of linear momentum?

In elastic collisions, the total kinetic energy of the objects before and after the collision is conserved, in addition to the conservation of linear momentum. In inelastic collisions, some of the kinetic energy is lost and converted to other forms of energy, but the total momentum is still conserved.

## 5. How does the law of conservation of linear momentum relate to Newton's third law of motion?

The law of conservation of linear momentum can be seen as a consequence of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. In a closed system, the internal forces between objects will cancel out, resulting in the conservation of momentum.

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