The conservation of momentum in 2D

In summary, the homework problem involves two hockey pucks of equal mass undergoing a collision on a hockey rink. One puck is initially at rest, while the other is moving with a speed of 5.4m/s. After the collision, the velocities of the pucks make angles of 33 degrees and 46 degrees relative to the original velocity of the moving puck. The task is to determine the speed of each puck after the collision using the equation for conservation of momentum. The problem involves breaking the velocities into components and using trigonometry and the Pythagorean theorem to solve for the final velocities. A drawing of the resultant momentum vectors may also be helpful in solving the problem.
  • #1
Dakkers
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Homework Statement


Two hockey pucks of equal mass undergo a collision on a hockey rink. One puck is initially at rest, while the other is moving with a speed of 5.4m/s. After the collision, the velocities of the pucks make angles of 33 degrees and 46 degrees relative to the original velocity of the moving puck. Determine the speed of each puck after the collision.

(Assuming the moving puck is object A and the stationary puck is object B)
Ma = Mb
Va1 = 5.4m/s
Vb1 = 0m/s
Deflection Angle of A = 33
Deflection Angle of B = 46

Homework Equations


p(before) = p(after)


The Attempt at a Solution


Okay, the first thing I did was broke it into components as it's in two dimensions. For x,

p(before) = p(after)
(Ma)(Va1x) + (Mb)(Vb1x) = (Ma)(Va2x) + (Mb)(Vb2x)
(5.4) + 0 = Va2x + Vb2x
5.4 = Va2x + Vb2x

for y,

p(before) = p(after)
(Ma)(Va1y) + (Mb)(Vb1y) = (Ma)(Va2y) + (Mb)(Vb2y)
0 + 0 = Va2y + Vb2y
Va2y = -Vb2y

And then I don't know where to go from there. I've thought about trig and using Pythagorean theorem but there's too many variables.
 
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  • #2
Set up a drawing of the resultant momentum vectors after the collision. Trig and pythagorean theorem might be necessary here but draw a picture first and see what you can deduce from it.
 

FAQ: The conservation of momentum in 2D

What is the conservation of momentum in 2D?

The conservation of momentum in 2D is a fundamental principle in physics which states that in a closed system, the total momentum will remain constant. This means that the total amount of momentum in the x and y directions will remain the same, even if individual objects in the system are moving and colliding with each other.

How does the conservation of momentum apply in two-dimensional motion?

In two-dimensional motion, the conservation of momentum applies in the x and y directions separately. This means that if the total momentum in the x direction is conserved, it will not affect the momentum in the y direction, and vice versa. This allows for more complex interactions and collisions between objects in two-dimensional space.

What are some real-life examples of the conservation of momentum in 2D?

One example of the conservation of momentum in 2D is a game of pool, where the balls collide and transfer momentum to each other in both the x and y directions. Another example is a rocket launch, where the rocket's momentum in the x direction is conserved, while the exhaust gases propel the rocket in the y direction.

How is the conservation of momentum in 2D related to Newton's Third Law of Motion?

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This is directly related to the conservation of momentum in 2D, as the momentum transferred from one object to another during a collision is equal and opposite in direction, thereby conserving the total momentum in the system.

What are the implications of violating the conservation of momentum in 2D?

If the conservation of momentum in 2D is violated, it would mean that momentum is not conserved in any direction and the laws of physics would not hold true. This would have major implications in understanding and predicting the behavior of objects in motion, and would require a re-evaluation of our current understanding of physics.

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