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Its A since energy stored by stretching is always 0.5 * force * extension which is the area under the graph when taken graphically.
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Physics: Post your doubts here!
- Thread starter XPFMember
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Its A since energy stored by stretching is always 0.5 * force * extension which is the area under the graph when taken graphically.
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The ball hits the wall with momentum of mu.
Momentum is a vector.
Lets consider "--->" to be positive. So the ball hits the wall with momentum mu.
If the ball rebounds with same speed then it is elastic collision as KE is conserved.
The resultant momentum has to be big enough to counteract the force AND send it flying back with momentum mu.
So taking -----> as positive, mu - 2 mu = - mu
so now that ball is traveling at a momentum mu towards left <------
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Change in momentum = Pf - Pi = -mu - mu = -2mu. Pf = -mu coz when the ball rebounds it travels in opposite direction.
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Exaclty.
There is already a force of mu acting ---->
to stop the ball, momentum of mu acting <------- is needed.
To make the ball go with mu in <----- direction, further momentum of mu is needed.
mu + mu = 2mu <------ this way.
As momentum is vector, if -----> is +, then <----- is -.
So -2mu
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How to add up spring constants?
(springs in series and parallel)
(springs in series and parallel)
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Exactly what i was searching for XD
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Why is the answer C ?
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According to energy conservation law, total energy can never be changed. Energy can never be destroyed.
When the object strikes anything. If it is an inelastic collision, the kinetic energy is given off at collision as sound energy or thermal energy or some other form of energy ( see.. energy is given off.. not destroyed).
Therefore KE lost is dissipated and is not conserved.
Now you may ask : How is possible given that the formula of momentum is mv and the formula of kinetic energy is 0.5mv^2; both are dependent on mass and velocity.
Let's take an example with simple numbers :
1+2=3
3+0=3
This can represent the momentum conservation. Now look at the sum of squares :
1*1+2*2=5
3*3+0*0=9
The sum is not conserved because the momentum that was transferred changed differently the result of the squares. In a word, kinetic energy doesn't change linearly with speed (which is obvious since it's a square).
Hope this helped
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Can someone please explain this?
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According to energy conservation law, total energy can never be changed. Energy can never be destroyed.
When the object strikes anything. If it is an inelastic collision, the kinetic energy is given off at collision as sound energy or thermal energy or some other form of energy ( see.. energy is given off.. not destroyed).
Therefore KE lost is dissipated and is not conserved.
Now you may ask : How is possible given that the formula of momentum is mv and the formula of kinetic energy is 0.5mv^2; both are dependent on mass and velocity.
Let's take an example with simple numbers :
1+2=3
3+0=3
This can represent the momentum conservation. Now look at the sum of squares :
1*1+2*2=5
3*3+0*0=9
The sum is not conserved because the momentum that was transferred changed differently the result of the squares. In a word, kinetic energy doesn't change linearly with speed (which is obvious since it's a square).
Hope this helped
What i really needed to know was why momentum is conserved but thanks anyway for this and all the other questions you helped me out with today!
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why? displacement can decrease.. its distance that cannot
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Yes. Displacement can decrease. But it shouldn't in your case.
Tell me where the displacement is taken from
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why ? as the velocity is changing its direction , the gradient has to become -ve no?
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If two sprinsgs are in parallel then spring constant = 2k
If three sprinsgs are in parallel then spring constant = 3k
And so on...
If two springs are in series then spring constant = k/2
If three springs are in series then spring constant = k/3
And so on..
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Velocity is not changing direction. If it is, then the ball should NOT be traveling with constant velocity. It should be decelerating.
If you are taking the displacement from the start position, and the ball is continuously rolling, the displacement should only increase. NOT decrease.
If I have misunderstood your question and the ball is going to come back up the slope THEN your answer is correct
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The momentum of the system is always conserved wehther it is elastic collision or inelastic collision.
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can anybody plzzzzz tell about what is mechanical work and mechanical energy