Two objects with springs collide

  • Thread starter Thread starter sarmstrong
  • Start date Start date
  • Tags Tags
    Springs
Click For Summary
In this discussion, two blocks with different masses collide while equipped with identical springs, raising questions about the distribution of kinetic energy during compression. The user seeks clarification on whether the springs split the kinetic energy equally and expresses confusion about their calculations. Responses highlight that the springs compress together, sharing the compression and energy, and suggest analyzing the problem from the center-of-momentum frame for better understanding. Additionally, it is noted that the blocks do not have equal and opposite momenta, which affects the dynamics of the collision. Understanding these principles is crucial for solving the problem accurately.
sarmstrong
Messages
1
Reaction score
0

Homework Statement


Two air blocks with masses 224 g and
130 g are equipped with identical springs
(k = 2490 N/m). The blocks move toward
each other with identical speeds of 1 m/s on a
horizontal air track and collide, compressing
the springs.
Find the maximum compression of the
spring attached to the 224 g mass.

Homework Equations





The Attempt at a Solution


okay so the thing that I don't understand is do the springs split the kinetic energy from the objects equally and if they do I still do not understand what I'm doing wrong.
 
Physics news on Phys.org
sarmstrong said:

Homework Statement


Two air blocks with masses 224 g and
130 g are equipped with identical springs
(k = 2490 N/m). The blocks move toward
each other with identical speeds of 1 m/s on a
horizontal air track and collide, compressing
the springs.
Find the maximum compression of the
spring attached to the 224 g mass.

Homework Equations





The Attempt at a Solution


okay so the thing that I don't understand is do the springs split the kinetic energy from the objects equally and if they do I still do not understand what I'm doing wrong.

Hi sarmstrong, welcome to Physics Forums.

It's hard to say what you're doing wrong if we can see what it is you're doing... can you show an attempt in detail?

Two identical springs in series behave overall as if they were a single spring with the same spring constant; the compression will be shared, so half can be attributed to each.

Have you considered looking at the problem from the center-of-momentum frame of reference? In that frame the center of collision remains fixed in place, so both masses come to rest at the same instant with both springs as fully compressed as they're going to get. Kinetic and potential energy are conserved ...
 
sarmstrong said:
okay so the thing that I don't understand is do the springs split the kinetic energy from the objects equally and if they do I still do not understand what I'm doing wrong.
What would happen if you had two blocks (as above) without springs, but there is a spring attached to the track that they both hit at the same time?

See - during the collision, you have two blocks with a single spring between them.
(careful - the blocks do not have equal and opposite momenta)
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

Replies
17
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
Replies
3
Views
1K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
8
Views
6K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K