Wall Definition and 756 Threads

Homework Statement Calculate the change in momentum of a 120g pool ball hitting at 9m/s and rebounding at 6m/s. It rebounds at an equal and opposite angle of 45 degrees. Pi = 9m/s Pf = 6m/s angle = 45 degrees Homework Equations The Attempt at a Solution I have done all my...

Homework Statement A wave with the amplitude 4 cm travels along a rope that is fixed to a wall. The wave reflects from the wall. What is the amplitude of the reflected wave? Homework Equations I know it's something with light, could you explian in more detail? The Attempt at a Solution

1. Two steel balls A and B are placed inside a right circular cylinder, of diameter 54 cm making contacts at points P, Q and R as shown in the figure. The radius rA = 12 cm and rB = 18 cm. The masses are mA = 15 kg and mB = 60 kg. The forces exerted by the floor at the point Q and the wall at R...

I have a power supply with an input of 115/230 VAC. There is no wall plug wired to it, just cut wires. I don't have much experience with this. If I wire this to a cord can I plug it into the wall (120 volts)?

Homework Statement This isn't really a homework problem, it's a passage in the lecture notes that I don't quite get wholly. So here's the passage: "To compute the hydrostatic force on a semicircular wall of radius a which forms the end of a swimming pool filled with water, between D(y) = 0 and...

Hi all I have a revision question I am having some trouble with A cold room has a wall measuring 5.2m by 2.5m. The wall is constructed of 120mm thick brick on the inside, a cork layer 80mm and a 30mm layer ow wood in the outside. the inside temperature is -4ºC and the outside temperature...

Hello, I am working on a project this summer and I have run into a problem that I need a bit of help with. If I heat a fluid (water or some refrigerant) in a pipe with cross sectional area A and the fluid has a velocity V through the pipe then how long does the pipe need to be for a given heat...

Homework Statement A two-dimensional incompressible flow takes place in the space between two parallel solid plane boundaries, which are a distance 2b apart. The density of the fluid is p, the dynamic viscosity is p. and the velocity distribution in the flow is given by the expression I...

How would I go about calculating the hydrostatic force on the walls of an upright Cylindrical Tank. To keep it simple, it is completely full of water, is 1m tall, has a diameter of 1m. Many thanks for anyone that can help.

Homework Statement A ladder of length L is leaning against a frictionless wall. The floor is frictionless too. It starts to fall. At what angle will it leave the wall. Homework Equations The Attempt at a Solution I can derive the equation of motion...

Refer to the attached picture, condition : assume steady state legend : red : insulated (adiabatic) black : no condition Green : Temperature distribution, T(X) I started with figure A, from heat equation, A u will get the distribution with is just a constant...

Homework Statement A pendulum hangs from an inclined wall. Suppose that this pendulum is released at an initial angle of 10 degrees and it bounces off the wall elastically when it reaches an angle of -5 degrees. What is the period of this pendulum? Homework Equations T=2π√(l/g) The...

We have a water pipe which is 750mm diameter assumed running full with a flow rate of 152l/s. When the water exits the pipe there is a steel wall approx 1.2m in front of it and I need to determine the force that the water exerts on the wall? I have claulcated that the water is running at...

If you were to push a wall and it were to not accelerate, would this mean you did not apply force to the wall according to the equation F=ma?

Do wooden wall or window glass give good protection from penetrating radiation such as gamma rays?

A ball is spun in a vertical circle on a string. A light is shining from the side of the circle so that a shadow of the balls motion is shown on a wall behind it. The shadow is simply a circle moving up and down in a straight line (I can't attach the image). The amplitude of the shadow is 0.5m...

HIGH (800C+) wall temperature measurements - experimental help! Hi All - I'm seeking some advice from any experimentalist types. I'm working on a project analyzing heat transfer properties of exotic fluids. We have a simple experimental setup: laminar flow in a small diameter stainless steel...

Homework Statement An electron is trapped in a 1D potential described by: V(x) = 0 if x < R0 V(x) = infinity if x > R0 Electron is in lowest energy state, and experiment shows that: (\Delta)x = sqrt(<x2> - <x>2) = 0.181 x 10-10 Show that <x> = 0.5R0 Homework Equations...

Problem: A race car skidding out of control manages to slow down to 90km/h before crashing head-on into a brick wall. Fortunately, the driver is wearing a safety harness. Using reasonable values for the mass of the driver and the stopping distance, estimate the average force exerted on the...

Homework Statement I am trying to find the temperature profile through a cylinder wall. It is a one dimensional, steady state conduction problem without internal heat generation Homework Equations d/dr(r*dT/dr)=0 where r is radius and T is temperature The Attempt at a Solution I...

Homework Statement 4.80×10^23 nitrogen molecules collide with a 16.0 cm^2 wall each second. Assume that the molecules all travel with a speed of 410 m/s and strike the wall head on. Answer in pascals Homework Equations P=mv/A The Attempt at a Solution Ordinarily I would use...

Homework Statement A 261 g hockey puck is sliding on ice with a speed of 5.34 m/s hits a wall at an angle of 27.3° to the wall and bounces back at the same angle with the same speed. a) If the wall and the hockey puck are in contact for 10.9 ms, find the magnitude of the impulse on the...

Homework Statement A 259 g hockey puck is sliding on ice with a speed of 5.34 m/s hits a wall at an angle of 34.8° to the wall and bounces back at the same angle with the same speed. If the wall and the hockey puck are in contact for 11.3 ms, find the magnitude of the impulse on the puck...

Homework Statement The scale on a map is 1:25000. The length of a wall on the map is 3.2 mm. Find the actual length in metres.Homework Equations The Attempt at a Solution

Hey everyone! Got an interesting problem here, I am thinking I did it correctly but I wanted to see your opinions. Here is the problem.. A 0.2-m-thick plane wall is constructed of concrete. At steady state, the energy transfer by conduction through the wall is 0.15 kW/m2. The inside...

Homework Statement The owner of a small restaurant needs to move a table in order to have space for a new display. Ordinarily, a lamp of mass m is hanging over the table, suspended from a string attached to the ceiling. With the table in a new position, the lamp needs to be moved. To this end...

For my research I am going to be testing a swept wing in a wind tunnel. Currently I am looking into tunnel wall corrections and I was wondering if anyone knows of somewhere I can get uncorrected and corrected experimental data on a swept wing in a wind tunnel so that I can test out the...

Homework Statement A hockey-disk with mass m, radius "r" collides with a wall in an angle "alpha" with velocity "v". There is friction, but the place where the ball touches the wall doesn't slide. How does the velocity component that is parallel to the wall change? The collision is completely...

Homework Statement Calculate wall loss rate in BTUs per hour. For a 10 ft by 10 ft room with an 8 ft ceiling, with all surfaces insulated to R19 as recommended by the U.S. Department of Energy, with inside temperature 68°F and outside temperature 28°F: heat loss = \frac{Q}{t} = \frac{(Area)...

Homework Statement Two light sources half a millimetre apart with a wavelength of 550nm shine on a wall exactly 50cm away. What is the distance between the centre point on the wall and the 10th bright spot out? Homework Equations x=nLv/d The Attempt at a Solution...

Homework Statement To measure the static friction coefficient between a 1.64-kg block and a vertical wall, the setup shown in the drawing below is used. (The dots are only there because spaces didn't work) ......| ......|W SPRING----->(Block)|A ......|L ......|L ......| A spring (spring...

Hi - I'm just starting to build a few basic circuits and am looking to get easy access to a low voltage ac power supply. I pulled apart a power brick, and it only has 4 diodes, a cap, and a transformer. If I pull out the cap and the diodes and solder the cord to the leads on the transformer, I...

Homework Statement How thick a concrete wall would be needed to give the same insulating value as 3.5 inches of fiberglass? Homework Equations Q = -A·k·ΔT/Δx k = -Q·Δx/A·ΔT The Attempt at a Solution So here, k is equal to the insulating value, and since I want the insulating value...

For what it's worth, I came up with this problem, so perhaps it cannot be solved, or there could be a way to solve it without using all of the information given. Homework Statement A chair rests on a weighing scale and a wall. The relevant surfaces of the scale and the wall are...

Homework Statement a ball w/ mass of .15kg and a velocity of 5m/s strikes a wall and bounces right back with v=3m/s. ball is in contact with wall for 0.1 sec, how much force did the wall exert on the ball? Homework Equations Ft=mvf-mvi F=? t=0.1 m=.15 vf=3m/s vi=5 The Attempt at...

Homework Statement I HAVE PROBLEM and please help me the question is : how can I draw free diagram mass on the wall mass : 12kg fa : 45 angle 30 Kinetic coefficient of friction:0.25 find net f Homework Equations l can not draw the free diagram fx=0 fy=ma l don't sure l used...

Homework Statement A 0.1 kg rubber ball and a 0.1 kg clay ball are both thrown at the wall with the same initial velocity. the rubber ball bounces, the clay ball sticks. Which exerts a larger impulse on the wall?

Homework Statement You are trying to quickly make breakfast for school. You plug a cofee maker which uses 1200 W into a plug and then plug a toaster of 1800 W into the same electrical outlet. Will the circuit be able to make the load if the circuit breaker is rated 15 A? W1 = 1200 W W2 =...

NOTICE: THIS IS NOT AN ACTUAL HOMEWORK PROBLEM. Homework Statement A projectile is launched from a hill 2m high 8m away from the base of a slanted wall at a velocity v at an angle of 35 degrees from the horizontal. The equation of the slanted wall is y = 2.8x. The slanted wall is 20m high...

Homework Statement This is a two part problem I figured out the 2nd part but not the first. a) A 7.3 m ladder whose weight is 364 N is placed against a smooth vertical wall. A person whose weight is 810 N stands on the ladder a distance 2.7 m up the ladder. The foot of the ladder rests on...

In a period of 1.1 s, 5.0 x 10^23 nitrogen molecules strike a wall of area 9.0 cm^2 . If the molecules move at 260 m/s and strike the wall head on in a perfectly elastic collision, find the pressure exerted on the wall. (The mass of one N2 molecule is 4.68 10-26 kg.) Molar mass=mass of...

Homework Statement One end of a uniform meter stick is placed against a vertical wall . The other end is held by a lightweight cord that makes an angle θ with the stick. The coefficient of static friction between the end of the meter stick and the wall is 0.38. What is the maximum value the...

Homework Statement The person in figure 8.31 weighs 800 N. the forces F1 and F2 have magnitudes of 100 N and 900 N respective. Assume the force of gravity acts downward through point A as shown. Determine the net torque on the person about axes through points A, B, and C perpendicular to the...

Homework Statement A 1.0 kg wood block is pressed against a vertical wood wall by a 12 N force (into the wall, at a 30 degrees angle up from the horizontal). if the block is initially at rest, will it move upward, move downward, or stay at rest? The attempt at a solution ive written...

I'm having trouble with understanding how to calculate a wall thickness change in a hollow cylinder unde axial loading. The length, outside diameter and initial wall thickness are given as well as the size of the load, Young's modulus and Poisson's ratio. I guess this isn't really a hard...

My teacher just explained to us Newton's Third Law, and one example she used was her pushing against a wall. She stated that the net force would equal zero because the wall was pushing back, but that doesn't make sense to me... What I was thinking was that the force of her pushing was weaker...

I was given a problem based on statics and I was wondering if anyone could help. A window washer attempts to lean a ladder against a frictionless wall. He finds that the ladder slips on the ground when it is placed at an angle of less than 75◦ to the ground but remains in place when the angle...

Homework Statement Weight of sphere = W and a force P is applied on its surface to attain equilibrium (Friction is present). Then 1. Pmin = √3W/2 2. Pmin = (√5-1)W/2 3. When P is minimum, Angle of friction max between sphere and wall is cos-1 (√5-1)/2 4. When P is minimum, Angle of...

Hi everybody, Any one can tell me why the momentum of the wall is 2mv while a ball collides it?

Homework Statement A projectile, initial speed v = 20 m/s is supposed to hit a target D = 28.9 m away. However an H = 10 m high wall is placed halfway between the launching point and the target. What is the appropriate elevation angle? (in degrees). Homework Equations...