Conservation of momentum problem

In summary, the problem involves a 120g arrow moving at 75m/s striking and sticking in a 3.63kg wooden block at rest. With a coefficient of friction of 0.409 between the block and the table it sits on, the block will slide a distance of 2.4m/s before stopping. The friction force is calculated to be 14.5N. An alternative approach could be using energy calculations to determine the distance the block will slide.
  • #1
stonecoldgen
109
0

Homework Statement


a 120g arrow moving at 75m/s strikes and sticks in a 3.63kg wooden block, initially at rest. If the coefficient of friction between the block and the table it sists on is 0.409, how far does the block slide before stopping?


Homework Equations


m1v1+v1+m2v2=m1v1'+m2v2'

fr=mu(coefficient of friction)mg=sigmaF+fr

maybe:
v'=v+2ad

The Attempt at a Solution


I substituted values for the conservation of momentum equation

m1v1+v1+m2v2=m1v1'+m2v2'
(.12)(75)+(3.63)(0)=(.12)v1'+(3.63)v2'
9=3.75v' (v1' and v2' are the same as they are now ''the same piece'')
v'=9/3.75
=2.4m/s

so i figured out how fast the arrow stuck on the block would go

now, i would calculate the friction force i guess (.409)(3.63)(9.8)=14.5N

but i have no time, therefore no acceleration and don't know what to do
 
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  • #2
Welcome to PF, Stonecoldgen!
Not that it matters much, but add the mass of the arrow in that friction force calc.

I wonder if you could get the last step via an energy calculation?
Kinetic energy converted to work against the friction force.
 

Related to Conservation of momentum problem

1. What is conservation of momentum?

Conservation of momentum is a fundamental principle in physics that states that the total momentum of a closed system remains constant over time. This means that the total amount of momentum before a collision or interaction is equal to the total amount of momentum after the collision or interaction.

2. How is conservation of momentum applied in real-world situations?

Conservation of momentum can be applied in many real-world situations, such as collisions between objects, explosions, and rocket propulsion. It is also used in fields like engineering, mechanics, and astrophysics to understand and predict the behavior of systems.

3. Can momentum be created or destroyed?

No, according to the law of conservation of momentum, momentum cannot be created or destroyed. It can only be transferred from one object to another or converted into other forms of energy.

4. What is the formula for calculating momentum?

The formula for momentum is p = mv, where p is momentum, m is mass, and v is velocity. Momentum is measured in units of kilogram-meters per second (kg m/s).

5. How does the conservation of momentum relate to Newton's laws of motion?

The conservation of momentum is a direct consequence of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. This means that when two objects interact, the total momentum before and after the interaction must be equal, in accordance with the law of conservation of momentum.

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