Block Definition and 998 Threads

Homework Statement Assuming no friction is on the plane or the pulleys and the pulley and rope have negligible mass... Determine the acceleration of each block and the tension in each cord. Block A weighs 100kg, Block B weighs 300kg. Homework Equations ΣF = ma ma = 100kg mb = 300kg The...

Homework Statement A block of mass m = 2.00 kg is released from rest at h = 0.300 m above the surface of a table, at the top of a θ = 50.0° incline as shown in the figure below. The frictionless incline is fixed on a table of height H = 2.00 m. a. Find a on the incline a=7.51 :) b. Find V(f)...

Homework Statement A concrete block of mass 25kg is placed on a smooth slope that makes an angle of 30 degrees with the horizontal. Ignoring the effects of air resistance, calculate a) the acceleration of the block as it slides down (g = 9.81 ms-2) b) the distance the block moves in 3 seconds...

Homework Statement Find the time it takes for block A to slide 0.5m on block B. Mass A=10 kg Mass B=35 kg I included a screen shot from my online homework. Homework Equations FR=FNμkThe Attempt at a Solution For Block A: mAa=T-FRA-WAsin(30) T=10a+68.67 For Block B: FRC=(mAg+mBg)μBC FRA=mAgμAB...

Hi, I was wondering if I could make my house a big Faraday cage capable of blocking Wifi and cellphone signals from the outside by covering all of the inside walls with chicken wire? How big of a problem is it that windows would stay uncovered? Or that electrical wiring inside the wall (so...

Just got confused that while applying the Work - Energy Theorem in a vertical Spring-Block system performing SHM (considering no other external forces other than gravity), when I apply the theorem from equilibrium position, do I consider the work done by gravity?

Homework Statement MECHANICS: Given Theta, L, M, and acceleration of elevator relative to ground. Find the time it takes for the block to reach the end of the incline. Here is a diagram: http://k-elahian.com/tmp/nip.PNG Homework Equations f=ma kinematics relative acceleration The Attempt...

Homework Statement "A block is projected up a frictionless inclined plane with initial speed v0 = 3.50 m/s. The angle of incline is θ = 32.0°. (a) How far up the plane does the block go? (b) How long does it take to get there? (c) What is its speed when it gets back to the bottom?" Homework...

Homework Statement A 7 kg block on a flat surface moves from 2 m/s to 4 m/s over 5 m. The coefficient of friction between the block and the surface is 1. How much force was used to move the block? Homework Equations Honestly, my physics instructor gave us so many worksheets with so many...

Homework Statement Three blocks of identical mass are placed on a frictionless table as shown. The center block is at rest, whereas the other two blocks are moving directly towards it at identical speeds v. The center block is initially closer to the left block than the right one. All motion...

I came across this description of the block theory of time. From my understanding, it is completely wrong, but would like someone else to evaluate it. "The block theory of time (we’ll call it) might be described like this. Suppose events are like villages or locations along a train track. You...

Homework Statement A 20.0-kg block is connected to a 30.0-kg block by a string that passes over a light frictionless pulley. The 30.0-kg block is connected to a spring that has negligible mass and a force constant of 250 N/m. The spring is unstretched when the system is as shown in the figure...

1. The block of 50kg with m =30kg is in the verge of moving down the slope where theta = 20degree, determine the new value of m when the mass of block is increased more to 20kg . Homework EquationsThe Attempt at a Solution I have done in this way , is it okay ? (50-30)(9.81) = Fs 196.2 = Us...

Homework Statement The block of weight of 100N is pulled by a rope over a pulley of small block with m kg . A 200N forec also acts horizontally as shown . If thge kinetic coefficient = 0.25 , static coefficient = 0.3 , determine whether the block is moving when the block is in moving or...

Homework Statement [/B] A student wants to find the refractive index of a rectangular block of glass. He draws around the block and marks the position of a ray of light that travels through the block. With the block removed, the student can draw in a normal line and then measure the angle of...

Hi, I have a doubt. Why pain occurs in a coronary artery block. I can understand, heart cannot work efficiently if blood sent to is less. It may lack oxygen and other nutrients. It can even fail to perform or even be dead. But why there should be a pain? What is the role of pain and how...

Homework Statement A 3 kg wood block is launched up an inclined wooden ramp that has an angle of 25° to the horizontal. the Block's initial speed is 12 m/s and the kinetic coefficient of friction is 0.2. What is the vertical height the block reaches above it's starting point? What speed does it...

Homework Statement A bullet goes through a block and covers a distance D with a velocity of V0=200m/s. Calculate the velocity that the same bullet has AFTER passing through another block of the same material but which has half the width of the initial block. Homework EquationsThe Attempt at a...

This isn't actually a problem. It is a doubt which I have about wedges according to Newton's Laws Consider a friction less wedge, of mass 'M', inclined at angle θ, placed on a smooth horizontal surface, on which a block of mass 'm' is placed. The block exerts some normal force perpendicular to...

Homework Statement A light inextensible string of length l hangs on two pegs attached to parallel walls separated by a height. A small frictionless pulley of weight Wp is attached to a block of weight Wb. When it is placed on the string, the string becomes taut and pulley runs on the string...

I am reading An Introduction to Rings and Modules With K-Theory in View by A.J. Berrick and M.E. Keating (B&K). I need help with Exercise 1.2.9 (a) ... Exercise 1.2.9 (a) reads as follows:https://www.physicsforums.com/attachments/5101I am somewhat overwhelmed by this exercise ... can someone...

Homework Statement Determine the closed loop transfer functions of the systems shown below: Homework Equations Standard block diagram algebra. The Attempt at a Solution I've moved the take off point such that the diagram now looks like: I am having difficulty determining G1(s). The...

Homework Statement A 0.5 g pellet is fired horizontally at two foam squares resting on a frictionless tabletop. The pellet rips through the first block (mass = 1 kg) and embeds itself in the second block (mass = 0.5 kg). As the bullet interacts with the blocks, it causes them to move with...

Homework Statement A 2kg block slides down a 3 m long ramp that is inclined at 40 degrees. The coefficient of friction is .2 What is the velocity when it hits the bottom of the ramp? Homework Equations Kinetic = 1/2 mv^2 Potential = mgh Work of friction: Fnμ*(displacement) The Attempt at a...

Homework Statement A 4.00-kg block rests on a 30.0 degree incline. If the coefficient of static friction between the block and the incline is 0.700, with what magnitude force must a horizontal force act on the block to start it moving up the incline? Homework Equations F=ma...

Homework Statement A block of mass m is placed on a triangular block of mass M, which in turn is placed on a horizontal surface as shown. Assume frictionless surfaces. Find the speed of triangular block when the small block reaches the bottom end, Homework EquationsThe Attempt at a Solution...

This problem is an example from Mosca and Tipler, 9-13, 6th edition. I believe the books equation for the acceleration of the system is incorrect according to my work... Anyway, here goes 1. Homework Statement "Two blocks are connected by a string that passes over a disk pulley of radius R...

1. Homework Statement A block, of mass M1, on the rough slope shown is attached to another mass M2 by a light, inextensible string which passes over a frictionless pulley as shown in the diagram (the coefficient of friction between the block and the slope is u ). The block is released from...

Homework Statement A projectile of mass m = 50g traveling at v0 = 20m/s hits a block of mass M = 450g. The block rests on a frictionless horizontal surface and is attached to a spring of force constant k = 2000N/m. The projectile ricochets backward off the block with speed v’ = 0.6v0. The...

Homework Statement A small block sits at the midpoint of a 2.0 m plank lying on a level floor. A student slowly raises one end of the plank until the block starts to slide. At that instant, the raised end is 0.55 m above the floor. Find the coefficient of static friction between block and...

Homework Statement Find acceleration of block on the way down incline. The incline is 40 degrees and made of steel. The block is also made of steel. μs = 0.6 μk = 0.3 mass of block = 2.00 kg Homework Equations a = g (sinθ - μcosθ) a = F/mThe Attempt at a Solution My friend is getting 4.04...

PeterDonis submitted a new PF Insights post The Block Universe - Refuting a Common Argument Continue reading the Original PF Insights Post.

Homework Statement When an 8.0 N force is exerted horizontally on a 10.0 kg block, the block’s acceleration across a level surface is 0.2 m/s2. a. Find the coefficient of kinetic friction between the block and the surface. b. Find the frictional force on the block. c. Find the net...

Homework Statement A grinder consists of a 6.01 kg steel block on a 1.46 m long arm that spins around a table. If the angular acceleration is -1.62 rads/s2, what is the coefficient of friction between the steel block and the table? I'm having trouble with attempting the question, especially...

Homework Statement A block of mass m is placed on a triangular block of mass M which in turn is placed on a horizontal surface. Assuming friction less surfaces find the velocity of the triangular block when the smaller block reaches the bottom end.The angle of inclination of the plane is...

Homework Statement A block is held between two walls. One static, one applying a force. If the block weighs 5kg, and the coefficient of static friction between each wall and the block is 0.4, what horizontal force is required by the wall applying it? Do both walls contribute an equal vertical...

Homework Statement A 3.0 kg block is held against a spring with a force constant of 125 N/m. The spring is compressed by 12 cm. The ice is released across a horizontal plank with a coefficient of friction of 0.1 A) Calculate the velocity of the block just as it leaves the spring. Assume the...

Homework Statement Homework Equations (Conservation of momentum) (Conservation of energy) The Attempt at a Solution I know linear momentum must be conserved on the X-axis, so mvo=mv1x+Mv2 where v1 is the final velocity of the small mass and v2 is the final velocity of the large mass...

Homework Statement The whole problem is in variables, which tends to confuse me a little. We have two blocks that collide, Ma and Mb. Initially Ma experiences a positive velocity. Mb experiences a 0 velocity. Finally, Ma experiences a negative velocity, while we do not yet know Mb's final...

1. Homework Statement We are dealing with a block of 20 kg mass on a ramp that is at an angle of 30 degrees. The spring constant given is 500 N/m. Picture- https://flic.kr/p/A3aCsM The only difference is that that we are supposed to be holding the spring stationary, it isn't attached to a...

Homework Statement Homework Equations PCM ∑pi=∑pf v2=u2+2asThe Attempt at a Solution First, using the PCM equation, I found the final velocity of the block, which is about 10.5 ms-1. Then by using the SUVAT formula, i would be able to find the distance moved by the block, but I don't have...

I have been debating somebody and he says that if you drop one cinderblock from ANY height(onto 9 other ones) it will only destroy one cinderblock because it destroys itself in the process.I believe the higher up you drop, more blocks will be destroyed. Can someone tell which is correct and(most...

If you were to put a cap on your exhaust pipe your emissions will reduce thus you would solve the whole paranoia of climate shenanigans.

Homework Statement We are dealing with a block on an incline that you can alter the angle with. The inclination angle was increased until we reached a certain angle(critical angle) that the block just begins to slide at. Use this critical angle and your previous answers for the normal force...

Homework Statement A .5 kg block of cheese sits on a level table. The coefficient of static friction is .60. Three strings are tied together in a knot at a point, K. One string is tied to the cheese, the other on a wall at a 30 degree angle, and in the middle of those two strings a mouse hangs...

Homework Statement What is the speed after 5 seconds? Given Box1 : 400 kg Box2: 100 kg Initial velocity: 20 m/s μk: .30 Angle of Incline: 25 Time: 5 seconds Homework Equations Force of Friction: (mg)(cos θ)(μ) Effective Gravity: (mg)(sinθ) F=ma Vf = Vi + at The Attempt at a Solution For Force...

An inclined plane of angle θ = 20.0° has a spring of force constant k = 525 N/m fastened securely at the bottom so that the spring is parallel to the surface as shown in the figure below. A block of mass m = 2.31 kg is placed on the plane at a distance d = 0.312 m from the spring. From this...

Homework Statement Compute ##A^j~\text{for} ~~j=1,2,...,n## for the block diagonal matrix##A=\begin{bmatrix} J_2(1)& \\ &J_3(0) \end{bmatrix}##, And show that the difference equation ##x_{j+1}=Ax_{j}## has a solution satisfying ##|x_{j}|\rightarrow\infty~\text{as}~j\rightarrow\infty##...

Homework Statement Homework EquationsThe Attempt at a Solution Working from the reference frame of block , a pseudo force Ma0 towards right need to be applied on the cylinder . Forces acting on the cylinder are pseudo force , weight Mg and normal force from the block (if any) . Since the...

Suppose a block of 5kg is stationary on a table with μ_{s} = .15 and μ_{k} = .1 μ_{s}(F_{N}) = μ_{s}(mg)= .15(5)(10\frac{m}{s^{2}}) =7.5N μ_{k}(F_{N}) = μ_{k}(mg)= .1(5)(10\frac{m}{s^{2}}) = 5NThe force applied to the block is represented by the function: f(x) =...