7. ### I Does the wave function spread more quickly after it is observed?

For the sake of this question, I am primarily concerned with the position wave function. So, from my understanding, the wave function seems to 'collapse' to a few states apon measurement. We know this because, if the same particle is measured again shortly after this, it will generally remain in...
8. ### Describe the motion of yoyos suspended from the ceiling

I have trouble solving this problem any help would be appreciated. Problem statement ##J=\frac{mr^2}{2}## a) Determine the motion of yoyos for ##n=1,2,3## The case for ##n=1## is simple, however, I am having trouble with ##n=2## and ##n=3##. for ##n=2## I started by drawing all the forces...
9. ### I The definition of generalised momentum

Why, in lagrangian mechanics, do we calculate: ##\frac{d}{dt}\frac{\partial T}{\partial \dot{q}}## to get the (generalised) momentum change in time instead of ##\frac{d T}{dq}##? (T - kinetic energy; q - generalised coordinate; p - generalised momentum; for simplicity I assumed that no external...
10. ### A ball hitting a two-ball system (with a spring between them)

I honeslty don't quite know how to start. It seems like the Hooke's coefficent k is independent of the answer to this problem. I would also appreciate any clue of expressing the condition when "balls will collide again". The fact that all balls can keep moving make this rather difficult. It...
11. ### I Relativistic velocity, perpendicular acceleration and momentum

A stationary observer sees a particle moving north at velocity v very close to the speed of light. Then the observer accelerates eastward to velocity v. What is its new total velocity of the particle toward the north-west relative to the observer? I ask because while the particles total...
12. ### 2 contradicting approaches for a 1D elastic collision

So I've managed to confuse myself on this problem :) Since the problem says we can assume ##m_p << m_b##, I'm assuming that the velocity of the bowling ball will be unchanged, such that ##\vec v_{b,i} = \vec v_{b,f} = -v_{b,0} \hat i## I started out using the energy-momentum principle, ##(\vec...
13. ### Calculate speed from elastic and inelastic collisions? (momentum)

So to cut to the chase, I missed my class' lesson on momentum - have tried to catch up, quite successfully but am baffled about this question. I know the conservation of momentum etc. but after trying for ages it's just not happening this question so any help would be much appreciated, Oscar.
14. ### B Why do heavier projectiles tend to have higher momentum?

I am wondering why heavier bullets have a higher momentum than lighter bullets when using similar powder charges? At the muzzle, a typical 150 grain bullet fired from a 30-'06 will travel at around 3000 ft/s. A 200 grain bullet from the same rifle will travel around 2600 ft/s. (The velocities...
15. ### Collisions, Impulses and Impulsive Tension

1. When an object attached to a fixed point with a string, is given a velocity and the string goes taut. So it says in this book (Applied Mathematics 1 by L. Bostock and S. Chandler) that when the string goes taut, the component of the velocity of the particle becomes zero in the direction...
16. ### Momentum and Conservation of energy

When A hits B, COLM mV = -mVa + 2mVb V = 2Vb - Va COKE 0.5mv^2 = 0.5mVa^2 + 0.5(2m)Vb^2 V^2 = Va^2 + 2Vb^2 When B hits C COLM 2mVb=4mVc Vc = 0.5Vb COE 0.5(2m)Vb^2 = 0.5kx^2 +0.5(4m)Vc^2 sub Vc = 0.5b mVb^2 = KX^2 After that im stuck, cause i cant find V in terms of Vb only
17. ### Application of momentum conservation in inelastic collisions

So, what I did was suppose the mass of ramp is $M_r$ and let velocity at B of block be v, then, after inellastic collsion both bodies v' velocity at B , $$M\vec{v}= M_r \vec{v'}+ M \vec{v'}$$ or, $$\frac{M}{M +M_r} \vec{v}= \vec{v'}$$ Now, Suppose I take the limit as mass of ramp goes to...
18. ### B Two masses collide with a spring -- Find the final positions/velocities

Let's say you have two masses on either side of a spring. Mass 1 is connected to the end of a spring. The spring itself has no mass. Mass 2 is free in space. So you have: [M1]-[spring] [M2] So it's more descriptive, I'll name the variables like you might in programming. Let's define...
19. ### Momentum conservation in SHM

I first got the velocity of the combined mass with conservation of momentum and as it was in the mean position the velocity can be written as v = wA ( w= angular frequency , A = amplitude ) as we have to take it back to natural lenght i put A as the initial extension but i am getting a wrong ans...
20. ### Projectile-car system and momentum

I have done question 1. But I'm struggling with the other one. So since the only thing I know about the rocket is the mass and the velocity, I guess I have to use momentum to solve this problem. From the first question, I found out that the x-velocity of the projectile is ##v_x=5...
21. ### I Clebsch–Gordan coefficients: An Identity

Hi, everyone. I'm trying to get the next identity It is in the format <j1, j2; m1, m2 |j, m>. I hope you can help me
22. ### I can't comprehend impulse = momentum

Here is my calculation: F = ma 50N = 1050kg * a a = 0.0476m/s² S = ut + ½at ² 1000m = 0t + ½(0.0476)t² t = 204.980s y = 204.980s (time to travel 1000m) since impulse = momentum, F * t = mv F * x = m * distance covered/y 50N * x = 1050kg * 1000m/204.980s 50N * x = 5122.450N⋅s x = 102.440s...

24. ### Physics momentum problem -- Collision between 2 blocks that stick together

So far I found the answer for a and b, but when I attempted to do the other ones I was completely lost. A.) P= MV M = 25g = .025kg V = 18 .025 * 18 = .45kg*m/s B.) KE= 1/2 mv^2 1/2 (.025)(18)^2 4.05 J
25. ### Bullet penetrating a block

Change in KE = Change in thermal energy 0.5 * (6)* vblock^2 = 0.4 * 6 * 9.81* 0.1 vblock = 0.885 By Conservation of Momentum, (0.05)(854) = (0.05)*vbu + (6)(0.885) I am not sure whether Change in KE = Change in thermal energy is true coz there should be a change in internal energy of the...
26. ### I Heisenberg Uncertainty: simple explanation required please

why can't we know where electron goes after it was hit by light? Light has a travel direction, can't we assume that electron bounces to the same direction that the light was headed??
27. ### I To which particles does ##p=mc## apply?

In A.P. French's Special Relativity, the author said the following, As I understand, photons are massless, so I don't think the last equation above applies to photons, but then, when deriving it, he used an equation proper to photons (##E=pc##). So in which context is ##m=p/c## valid?
28. ### Simple Canon Question (Conservation Of Momentum): Frame of Reference

Since Pi = Pf, 0 = MbVbg + McVcg I just need to express Vbg in terms of Vbc and Vcg (that is, I need to express the velocity of the ball relative to the ground in terms that I know/want to solve for): by reference frames: Vbc = Vbg + Vcg so Vbg = Vbc -Vcg Now I can sub in and solve 0 =...
29. ### Conservation of Momentum: Elastic Collision of Two Masses

I really want to know which answer is correct. I don’t really know if I should include velocities to the left as negative velocities in the equation. Is it -1 or 4.33? Please help! Thanks!!!
30. ### Pushing a stalled car out of an intersection

Hints given: -Start with free body diagram. Use the relationship between impulse and momentum to find the final velocity of the car after he has pushed for time t. -Use a kinematic equation to relate the final velocity and time to the distance traveled. -What is his initial velocity? My...