Block Definition and 998 Threads

I am watching this video; at the 8:20 mark it shows that a proton in a magnetic field will align with the magnetic field very easily if there is no shielding from electrons, and therefore will require energy to shift to the opposite spin state; makes sense to me. I also understand that when...

Why doesn't the incline angle play a role in changing the ##m## component of this equation? ##T = 2π\sqrt{\frac{m}{k}}## FOR QUESTION 25, PART B: ANSWER:

Suppose a bullet with high speed strike a wooden block and move together after collision. We know there is loss in total KE of bullet-wooden block system. The question is, if the part of the loss in KE of the bullet is transfer to heat energy, HOW to prove the CONSERVATION of ENERGY in this...

Its a very basic problem and my friend suggested a solution that we should equate mg and kx ie mg=kx and just plug in m=8 and x=0.16 but i think that we should equate the energies like mgx=1/2kx^2 ie because at the point where mg will be equal to kx the mass will still have a velocity hence it...

I know the answer but don't understand the concept. The solution says the accelerations are the same but if the top block is at rest how can it be accelerating. I know you can view both blocks as the same system but can you not study them independently. Any help would be appreciated.

Hello! I am stuck on part of a problem and was wondering what I am doing wrong. For part a of the problem, we were asked to find the impact speed. I did this in a photo below given the following values: Θ = 30 degrees. The initial velocity = 10 m/s. The coefficient of kinetic friction = 0.4...

Hi everyone, just a quick question.. I tried this problem using Newtons laws, not conservation of energy, and I got an answer exactly half of what the correct answer is, and I'm not sure why. Here is what I did: Net force = zero once the spring is compressed, therefore mg - kx = 0 mg = kx...

(a) Ridiculously simple though it looks, I can't see how the string will be tight. One of the two has to be true. (1) The static friction ##f_S = mg \sin\theta = 25\times 10\times \sin 30^{\circ} = 122.5\; \text{N} ##. The maximum static friction ##f_S = \mu mg \cos \theta = 0.6\times 25\times...

Force along the horizontal would be T cos(theta) Frictional force (which is in the opposite direction )= μmg So net force in the direction of velocity = Tcos(theta)-μmg P= [Tcos(theta)-μmg]v But this is not so, the right answer is given to be Tvcos(theta). Why should we not consider the...

I called the block ##A## and ##B## the cylinder. For ##A##, in the non inertial system I wrote ##x) Fr_d -F=0## ##y) R-W_1=0## Where ##Fr_d## is the kinetic friction and ##R## the normal force on ##A## Then, I know that: ##a_{B/A}=a_B-a_A## ##0=a_B -a_A## ##a_A=a_B## ##v_{B/A}=v_B-v_A##...

I have some difficulties trying to understand non-inertial frames. I have problems to notice the acceleration in these cases, from an inertial reference frame and from non inertial refrence frame. Consider the first case, if I'm on the wedge, I see that the block doesn't move so there's no...

I considered the downwards direction and left direction as negative. For ##m_1##, Newton's equations are: ##x) Fr + W_x - T=0## ##y) N - W_y =0## For ##m_2##: ##y) T - W =0## Then, if I replace the data, I get ##T=22.2 N## and then ##m_2=2.2 kg##. With that, for the second question ##m_2=4.4...

Well, I'm having trouble with the free body diagrams. For ##A## we have ##y)## weight, normal force, contact force with ##B##, ##F . sin(36.8°)##. And the acceleration is ##0## because we want to calculate the maximun force before moving. ##\Sigma \vec F = m . a_y## ##\vec N_A + \vec F ...

I've taken intro to classical mechanics, but am really not sure about how this example calculates the friction force and the normal force...I usually break down the force vector into components, and I understand that this is probably a much more simple way to calculate the perpendicular and...

This is what happen to an aluminum block when a 0.5 ounce piece of plastic hits it at a speed 15,000mph in space. That's some serious impact! Just imagine what a heavier object could do traveling at the same speed.

Question as follows: My answer/explanation: Force needed to make block slide = static friction between block and plate. So friction = normal of block * static friction = (0.5∗9.8)∗0.9=4.41N(0.5∗9.8)∗0.9=4.41N My thoughts/wrong answer probably?: after block slips, plate experience kinetic...

Hey everyone I'm struggling on the last part of this assignment. I need to find the total work done by the block and the bullet, when the collision happens. The informations is: mblock=0.3 kg mbullet=0.01 kg vg=700 m/s Height=0.72m The final speed after the collision is vf=22.6 m/s and the...

This is the image provided with the problem, the values given include: d= 4.00 m, the mass of block one=0.200 kg, speed of block one=8.00 m/s, the period of oscillations for block two without friction=0.140 s, and the spring constant= 1208.5 N/m. I know how to solve the oscillations if block...

Does the block move along the pink dotted lines as attached in the figure below? I tried to draw the FBD of the small block ##m ## at the lowermost point which is also attached below.(The direction of ## v_0 ## is actually tangential) Is the figure above correct? If not, why?

I find this subject fascinating. Einstein said the distinctions between past, present and future is just a persistent illusion. I was watching a special with Brian Greene and other Physicist who think we do live in a Block Universe and they explained it very well. Here's my question. Say there...

A block of mass ##10kg## rests on a horizontal floor. The acceleration due to gravity is ##9.81 m/s^{2}##. The coefficient of static friction between the floor and the block is ##0.2##. A horizontal force of ##10N## is applied on the block as shown in the figure. The magnitude force of friction...

The equations i got are attached below. Is it right? If yes what should we do after this. I tried solving the equations, but i did not arrive at the solution.

The intensity, I of light in lumens, passing through the glass of a pair of sunglasses is given by the equation I(x) = I0 (0.8)^x , where x is the thickness of the glass in millimetres and I0 is the intensity of light entering the glasses. How thick should the glass be so that it will block 25%...

Sol: ##Mg.sinθ - μMg.cosθ = ma## ##a = g.sinθ - μg.cosθ## Now ##S = ut + \large\frac{1}{2}\normalsize at^{2}## but ##u = 0## ##t = \large\sqrt\frac{2s}{a} = \sqrt\frac {2s}{gcosθ(tanθ- μ)}## My questions: What is the meaning of " PQ = s" in the question? How ##t = \large\sqrt\frac{2s}{a}...

My attempt at the solution... I only have problem in solving part a) 1) i calculated the spring force actingbon the table block and it is greater than the frictionnand tension force acting in the opposite direction, so by that the block will move in left. 2) now i found that which forces are...

Here's the given F-t graph My Attempt... Fsmax=10N & Fk= 5N I made equatiom F=5t-5 ( by seeing Force force and Counteracting kinetic friction) reduced the formula to a=(5t-t)/2 wrote a=dv/dt and solved it but got wrong answer.

This is task from my textbook and it does not provide us with an answer. So I cannot verify if I did mistake. Can someone double check, please? My solution: ##E_{k_{0}} = \frac{(m+M)v_{0}^2}{2} \quad \land \quad U = \frac{kx^2}{2}## ##E_{k_{0}} = U## ##\Longrightarrow (m+M)v_{0}^2 = kx^2##...

Let v be the speed of the block and x elongation of the spring beyond the equilibrium point. Initially, v = 0 and x = 0. At the maximum elongation, the block also has v = 0, it has moved a distance equal to x (parallel to the plane) and the variation of height is equal to -x⋅sin(53°). W(FNC) =...

this is the question and solution given in the book solution i made below. only difference is i took x as opposite side that given in the book and wrote F=ma equation that way. as a result the left side of equation (3) directly turned negative. that caused difference in result but why? i mean...

How does one go about finding a matrix, U, such that U-1D(g)U produces a block diagonal matrix for all g in G? For example, I am trying to figure out how the matrix (7) on page 4 of this document is obtained.

Hello I hope someone can help me, as i am kinda stuck for the moment. As you can see, the assignment states that I need to find the poles from the closed loop transfer function. I plan on doing so, by using block diagram reduction method. This is as fare as I've come, and can't come...

Hello I hope someone can help me, as i am kinda stuck for the moment. As you can see, the assignment states that I need to find the poles from the closed loop transfer function. I plan on doing so, by using block diagram reduction method. This is as fare as I've come, and can't come further...

Consider a block on a sheet of paper. If the sheet is pulled without sliding the block, who has done work on the block (since it has undergone a kinetic energy variation)? I can not see another force doing work other than the static frictional force on the block.

W_net = Integral from 0 to 0.70 meters [ - F_spring - F_friction ] = 1/2 * (-k) * x^2 - mu * mg * normal force * x = 1/2 * (-325N/m) * (.70)^2 - 0.250 * 6kg * 9.81m/s^2 * 0.70 - 0 = - 89.93 Joules Is this correct and am I setting this whole thing up correctly? The negative signs have me...

Hermann Minkowski (Einsteins math instructor and a mathematical physicist himself): The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself...

I am looking at page 2 of this document.https://ocw.mit.edu/courses/chemistry/5-04-principles-of-inorganic-chemistry-ii-fall-2008/lecture-notes/Lecture_3.pdf How is the transformation matrix, ν, obtained? I am familiar with diagonalization of a matrix, M, where D = S-1MS and the columns of S...

Homework Statement The system is released from rest with no slack in the cable and with the spring stretched 225 mm. Determine the distance s traveled by the 3.2-kg cart before it comes to rest (a) if m approaches zero and (b) if m = 2.5 kg. Assume no mechanical interference and no friction...

Hello everyone:) I'm having an issue with an example problem in the book I'm using. I attached a pic of the problem and the book's solution. The issue I'm having is that I have no idea how the book got the velocity it did via the solution it presented. When I worked out the problem myself...

Homework Statement An oscillator consists of a block attached to a spring (k=400n/m). At some time t, the position (from equilibrium), velocity, and acceleration of the block are x= .100m, v= -13.6m/s, a= -123m/s^2. What is the frequency? mass of block? amplitude. Homework Equations position...

Hi all, Hopefully this is the right section of the forum to post in! I am a 5th year PhD student in physics at a prestigious university in the US. First 2 years I was taking classes and working in particle physics. On my 3rd year I transitioned to astrophysics. So in terms of the dedicated...

The problem is given in David Morin's Classical mechanics. Now, I jumped to solve part b of question. To find the number of bounces,we note that mass losses momentum of -2mV per bounce(This can be worked out from conservation of momentum and energy). Now initial momentum was MV. Then since per...

Homework Statement Assume that block A which has a mass of 30 kg is being pushed to the left with a force of 75 N along a frictionless surface. What is the friction force of block A on block B if the block B has a mass of 24 kg and is accelerating at 0.50 m/s2 to the right relative to the block...

Homework Statement Homework Equations Component of force,equilibrium of force. The Attempt at a Solution In the problem (ii),the friction force is ##Mgcosθμ##,the component of weight in the inclined surface is ##Mgsinθ## and the component of the applied force ##F## along the inclined surface...

Homework Statement A 28-g bullet is shot vertically into an 6-kg block. The block lifts upward 5mm (see the figure). The bullet penetrates the block and comes to rest in it in a time interval of 0.0010s. Assume the force on the bullet is constant during penetration and that air resistance is...

Homework Statement Block A is traveling down an incline plane of 35 degrees at 2m/s. It's pulling a 4kg block with a pulley and rope. Coefficient of friction is.12. How heavy must block A be ? Homework Equations F=MA F = WsinΦ + μWcosΦ mgh = 1/2 mv^2 + WD to overcome friction Vf^2 = u^2 +...

Homework Statement A layer of liquid with density ##800~kg/m^3## floats on top of a volume of water. A block floats at the oil-water interface with ##3/4## of it in water and the rest of it in the liquid. What is the density of the block? Homework Equations Buoyancy =##vρg## where ##v##=...

Homework Statement What is the mass of the block? Given: friction less surface, velocity at each marked point, distance between points 1 and 2, spring constant l = 7 N/m Homework Equations F=ma Kinematic equations The Attempt at a Solution I tried to solve for a in m = F/a in order to find...

Homework Statement A 2kg block is being pushed along a ceiling with friction by an angled force of 70 degrees. I'm asked only for the free body diagram. Homework EquationsThe Attempt at a Solution I figured both the gravitational and normal force would point downwards, but the force applied at...

Homework Statement Which graphy represents the potential energy of the block as a function of time? Homework Equations PE=mgh The Attempt at a Solution First, the potential energy is zero until it reache the top of the incline where the potential energy is maximum. Moving down, the potential...

(mentor note: not really a homework as the OP seeks understanding from an article) 1. Homework Statement I saw this on https://www.electronicshub.org/open-loop-system/, I thought the dry clothes should be the output, and heating the cloth should be the plant/process, I am so confused...