- #1
hello478
- 165
- 14
- Homework Statement
- image below
- Relevant Equations
- energy equations
My attempt:
my answer was b
correct answer is d
Question about the energy of 2 blocks with a spring between them
My attempt:
my answer was b
correct answer is d
- #2
BvU
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Can you explain why you picked b ?
Do you know the expression for kinetic energy?
Do you know the expression for kinetic energy?
- #3
hello478
- 165
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because before the release they are stationaryBvU said:
and it is elastic collision, maybe...
so the kinetic energies would add upto 0
so that the total KE is conserved...
- #4
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"Conserved" means "it is the same" throughout whatever is going on. Before release the sum of kinetic energies is zero because neither block is moving. If, as you claim, this sum is conserved, then neither block should be moving after release. Do you think that is the case?hello478 said:
- #5
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Why would kinetic energy be conserved? This would mean the blocks just remain stationary as kinetic energy is non-negative.hello478 said:
- #6
BvU
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BvU said:
- #7
hello478
- 165
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1/2 mv2
- #8
hello478
- 165
- 14
oh ok so, the velocities direction would not be considered.... thats the only thing i understand uptill now
- #9
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It sounds to me that based upon your many posts with seemingly little thought behind your attempts that what you really need to do before attempting these problems is to sit down with your book and try to understand the theory behind the problems first. Otherwise you will just be shooting wildly with your answers.hello478 said:
- #10
hello478
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ill try to do that, though i sort of know what the book says... physics is just not my thing so its difficult for me to graspOrodruin said:
when i read the book, everything is so easy until the questions blow my mind...
- #11
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Sort of know typically won’t do. You need to actually know and most of all understand what it says. Work through any derivations so that you understand where things come from, do the same with any examples. Go equation by equation and make sure you understamd how and why it came about.
- #12
BvU
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Tip (that worked for me): while reading, invent tough exercises you could test your classmates with.hello478 said:
Re 'not my thing': seems to me math isn't either. But systematic reasoning and logical thinking are indispensable in all fields! (what's yours?)
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- #13
hello478
- 165
- 14
ok ill try to do that too, but i dont have much time till my exams...BvU said:
and im a private student
so... i dont have classmates
and im currently doing physics AS levels and biology A levelsBvU said:
FAQ: Question about the energy of 2 blocks with a spring between them
What is the potential energy stored in the spring when it is compressed or stretched?
The potential energy stored in a spring when it is compressed or stretched is given by the formula \( \frac{1}{2} k x^2 \), where \( k \) is the spring constant and \( x \) is the displacement from the equilibrium position.
How does the mass of the blocks affect the system's energy?
The mass of the blocks affects the system's kinetic energy. When the spring is released, the potential energy stored in the spring is converted into kinetic energy of the blocks. The kinetic energy of each block can be determined using the conservation of energy and momentum principles.
What happens to the energy in the system if the spring is ideal and there is no friction?
If the spring is ideal and there is no friction, the total mechanical energy of the system is conserved. This means that the sum of the potential energy in the spring and the kinetic energy of the blocks remains constant over time.
How do you calculate the velocities of the blocks after the spring is released?
The velocities of the blocks after the spring is released can be calculated using the conservation of momentum and the conservation of energy principles. By setting up equations for both conservation laws, you can solve for the velocities of the two blocks.
What is the effect of different spring constants on the system's energy behavior?
The spring constant \( k \) affects the amount of potential energy stored in the spring for a given displacement. A higher spring constant means a stiffer spring, which stores more energy for the same displacement. This will result in higher kinetic energy of the blocks when the spring is released, assuming no energy losses.