Average Definition and 1000 Threads

In kinetic theory, the number of molecules hitting a unit area of a surface per unit time with speeds between v and v + dv and angles between \theta and \theta + d \theta is found to be a function of sin(theta) and cos(theta). There will often be a practice problem asking to show that the...

1. A car is traveling 9m/s Northwest. 8 seconds later it has rounded a corner and is now heading North at 15m/s. This was a question from my textbook and was an example question - so they supplied answers. I was able to work through all of it finding everything except the last question. They...

I found it somehow tricky to understand average speed and average power in mathematical fashion. I suppose general idea of taking average of some quantity is: sum of all values/number of values. how that idea fit's into idea of average speed=distance traveled/time traveled similarly, average...

This thread is prompted by a closed thread which left it’s OP’s original question unanswered. ->https://www.physicsforums.com/threads/average-wavelength-for-blackbody-radiation.423536/ The original question asked: is the ratio, of (a) the wavelength corresponding to the average energy in the...

1. Homework Statement In a theme park ride, a cage containing passengers falls freely a distance of 30 m from A to B and travels in a circular arc of radius 20 m from B to C. Assume that friction is negligible between A and C. Brakes are applied at C after which the cage with its passengers...

Homework Statement Find the average energy ##\langle E \rangle## for (a) an n-state system in which a given state can have energy 0, ε, 2ε, 3ε... nε. (b) a harmonic oscillator, in which a state can have energy 0, ε, 2ε, 3ε... (i.e. with no upper limit). Homework Equations Definition of...

If average of 11 numbers is 14 and average of the 9 of those numbers is 9, what is the average of the other 2 numbers? Answer 36.5 9x9 = 81 - how do I write equation to figure out other 2 numbers without trial and error?

Homework Statement A plane flies 413 km east from city A to city B in 49.0 min and then 814 km south from city B to city C in 1.70 h. For the total trip, what are the (a) magnitude and (b) direction of the plane's displacement, the (c) magnitude and (d) direction of its average velocity, and...

1. The problem: A hockey puck is hit on a frozen lake and starts moving with a speed of 11.6 m/s. Five seconds later, its speed is 7.4 m/s. What is its average acceleration? The acceleration of gravity is 9.8 m/s. Answer in units of m/s. What is the average value of the coefficient of kinetic...

Homework Statement A classical particle with total energy E moves under the influence of a potential V(x,y) = 3x3+2x2y+2xy2+y3. What is the average potential energy, calculated over a long time? Homework EquationsThe Attempt at a Solution I think that this can be solved using Virial Theorem...

According to the quantum mechanical free electron model the average energy is E=3EF/5 for the 3D case. Nevertheless I saw in a specialised physics book that for the 1D model the average energy at T=0 is 0 and wanted to know if it is the same for the 3D case.

Homework Statement A bascketball player , who has a weight of 890 N , jumps vertically with a height of 1.2 m , 1- Find his speed when he left the floor. 2- If the time that takes the basketball player to quit the floor is 0.3 s, what is his average acceleration ? (I don't understand this...

Hi all, Would anyone be able to let me know what the average frequency is for the human body? Also, what is the average frequency of a home? What would be considered abnormal? According to the Ofcom UK Frequency Allocation Table it notes different frequency uses e.g. a frequency of 1,600...

1. For the circuit shown in (Figure 1) , where V= 2.8 cos(2 t+ 0.3 ) , R= 8 Ω and C= 4×10−2 F , find the average power supplied by the source, Ps and the average power absorbed by the resistor PR .2. p (t) = v(t)i(t) = VmIm cos (ωt + θv) cos (ωt + θi) PR = (1/2)(V2m/R)3. From the...

Hi! I need help with the following question: A system has two energy levels, ε and ε1 that can be occupied by fermions (spin=1/2) that are non-interacting from a reservoir at temperature T and chemical potential μ. Compute the avarage occupation number of the state with energy ε. I have...

Homework Statement If the energy of a system depends on ##E = \alpha |x|## where ##\alpha## is positive, what is the average energy of the system? Homework EquationsThe Attempt at a Solution I've been given no information at all about the system beyond the energy. This is within a statistical...

$\tiny{205.o6.03}$ $\textsf{A body on a coordinate line such that it has a position}\\$ $\textsf{$\displaystyle s=f(t)=\frac{16}{t^2}-\frac{4}{t}$ on the interval $\displaystyle 1\le t \le 4$ with $s$ in meters and $t$ in seconds }$ $\textsf{a. Find the body's displacement and average vellocity...

Homework Statement Using the polar formula for an ellipse, and Kepler's second law, find the time-weighted average distance in an elliptical orbit. Homework Equations The polar formula for an ellipse: $$r = \frac { a(1-e^2)} {1 \pm e cos \theta},$$ Area of an ellipse: $$ A = \pi a b $$...

1. A baseball of mass 0.1 kg is moving horizontally at a speed of 40 m/s when it is stuck by a bat. It leaves the bat in a direction at an angle φ = 30◦ above its incident path and with a speed of 50 m/s. • Find the impulse the bat exerts on the ball. • Assuming the collision lasts for 0.0015...

Homework Statement Consider the 3 following Scenarios: 1. 2. rms value of line voltage is 208 V Three equal impedances, 60 +j30 W each, are delta-connected to a 230-V rms, three-phase circuit. Another three equal impedances, 40 +j10 W are wye-connected across the same circuit at the same...

I have 5 boxes and I am displaying the amount of hours it takes to complete 3 different steps with the materials inside said boxes (you don't need it, but its item removal, rebagging, and consolidation). However, there are different amount of bags inside each box, and I need to make a comparison...

I have a set of values I got from measurements, and each of these value has an uncertainty associated to it. I compute the average of my values. How can I average the uncertainty associated to my average value ? Do I simply take the average of all uncertainties ?

Homework Statement A particle of mass 5.0kg travels initially with a velocity of 8.0m/sˆı and then interacts with a particle of mass 6.0kg which was initially at rest. After the interaction the 5.0kg mass travels at a speed of 4.0m along a direction which makes an angle of 53◦ with the x-axis...

Hi, I would like to try and calculate the average distance traveled through a box of length ##w## by any straight path possible. As shown in the attached figure. Where the path through the box to an adjacent face is given by $$r_{adj}^2=\left(\frac{w}{2}-x\right)^2+y^2+z^2.$$ The average...

Homework Statement A golf ball is struck by a golf club and sent flying down range at an angle of 30 degrees to the ground and lands 150m downrange. If the mass of the ball is 0.045 kg and the collision of the ball and club lasted 0.01s, what was the average force applied by the club...

Homework Statement In which conditions the average speed equals the Average of the Speeds? Homework Equations Average speed= (Xf-Xo)/(tf-to) Average of the speeds= (vf+vo)/2 The Attempt at a Solution I tried to set up a formula for vf and vo, but it would be false to determine that vf=xf/tf...

Homework Statement Deep in space, there is a particle density, p, is 1.01cm^-3. Pressure is extremely low, P, is 5.1 x 10^-17 N/m^2. What is the average temperature of mostly empty space? Answer in K Homework Equations T=P/pKb The Attempt at a Solution I plugged in...

I am attempting to find the numbers above the average number of a set of numbers in an array. I am having trouble understanding why my output for the list of numbers above the average is so...weird. I'd appreciate the help! My code: public class Inequality { public static void main(String[]...

Homework Statement John is entering Steward, and drives West, with a Uav of 88 km/h. He arrives at Aurora, and realizes he took a wrong turn. He turns around and drives East, towards York, with a Uav' of 79 km/h. Steward-Aurora is 76 km & and Aurora-York is 34 km. For the whole trip (S -> A ->...

Homework Statement A 0.140kg baseball traveling 35.0 m/s strikes the catcher's mitt, which in bringing the ball to rest, recoils backward 11.0cm. What is the average force applied by the ball on the glove Homework Equations F=ma; FAB=-FBA The Attempt at a Solution Not sure where to start for...

Homework Statement A particle starting from rest revolves with uniformly increasing speed in a clockwise circle in an xy plane. The center of the circle is at the origin of an xy coordinate system. At t=0, the particle is at x=0.0m, y=2.0m. At t=2.0s, it has made one-quarter of a revolution and...

Homework Statement When iron is irradiated with neutrons an isotope of iron is formed. This isotope is radioactive with a half-value period (half-life) of 45 days. Give the meanings of the terms printed in italics. A steel piston ring of mass 16 g was irradiated with neutrons until its...

The total distance traveled by trains is 18 km & the time spent is 20 minutes. Find the average speed of the train in kilometers per hour. I' m stuck right in the beginning in converting 20 minutes to hours by dividing from 60 which I get this recurring decimal 0.33333

Homework Statement A(n) 8.5-kg object is sliding across the ice at 2.34 m/s in the positive x direction. An internal explosion occurs, splitting the object into two equal chunks and adding 12 J of kinetic energy to system. The explosive separation takes place over a 0.16-s time interval. Assume...

Homework Statement (a) Prove that the time average of the potential energy of a planet in an elliptical orbit about the sun is -k/a. (b) Calculate the time average of the kinetic energy of the planet. Homework Equations F = \frac {-dV} {dr} = - \frac {k} {r} The Attempt at a Solution [/B]...

Homework Statement [/B] I'm very stuck at answering parts (c) and (d) Homework Equations speed = Distance/Time The Attempt at a Solution

Homework Statement Homework Equations N/A The Attempt at a Solution [/B]

Homework Statement During several practice runs you stand at the end of a diving board and launch the basketball horizontally from a position 4.50 m above the water. If the average landing spot is6.25 m horizontally from your initial position, what is the average launch speed? Homework...

Homework Statement During a .0050 second time period a rocket expels 1.000kg of gas at a velocity of 5000 m/s. Calculate the rockets average Thrust, as well as Impulse. http://imgur.com/a/uE9dVI am going to use this note for reference on a test and want to rock solid about it. 2. Homework...

Homework Statement Homework Equations ∑Fav = mv2 - mv1 The Attempt at a Solution We have to separate v in x dir and y dir?

Homework Statement A particle of mass ##m## moves along a circle of radius ##R##. The modulus of the average vector of the force acting on the particle over the distance equal to a quarter of the circle is: zero if the particle moves with uniform speed ##v##. ##\dfrac{\sqrt2mv^2}{\pi R}## if...

After Dark Energy will tear our Universe apart, every Hubble sphere would contain only 1 or 0 gravitationally bound structures. What is an average size of such structures? (As I understand, galaxy clusters are the "seeds" of such remnants?)

Does anyone know how many times would an average protein fold in its lifetime? And how long do proteins live on average? Also, another quick question, somewhat related, any knowledge on how many "cascades" of different proteins making a conformational change on different new proteins can there...

Homework Statement So I have this homework exercise which I just can't seem to solve. It sound like this: "Half his time the cyclist was driving at the speed of 20km/h, half of the LEFTOVER way he drove at the speed of 16km/h. When his bike broke he finished his journey on foot at the speed of...

Hello everyone, The velocity and average velocity it is the same? The formula of the velocity is: distance / time or [L] / [T]. The average velocity is it equal? thanks

What is the occurrence rate of planets? I'm not talking about earth-like planets, but any planet in general. I can't find a source that examines this number, all I can find is the average number of earth-like planets. Can anyone lead me to a useful paper/source? Thanks in advance

My textbook talks about the average angular speed that ω = angular displacement / time for the angular displacement to take place. So the question is like there is m1v1 = m2v2, can the velocity be instead average angular speed to have the conservation of momentum equation like this? m1ω1 = m2ω2

Homework Statement The ammonia molecule (NH3) has a dipole moment of 5.0×10−30C⋅m. Ammonia molecules in the gas phase are placed in a uniform electric field E⃗ with magnitude 1.3×106 N/C . Part A: What is the change in electric potential energy when the dipole moment of a molecule changes...

Its my first time ever being in Physics and I need help with this probably really simple problem. It first says, a car is initially traveling at 25m/s and then coasts to a stop in 12 seconds. What is its acceleration? **I took 25/12 and got 2.08 m/s. Hopefully that part is right? Then it asks...

Homework Statement The wave function is given as Ψ(x,t) = Ae^[i(k1x-ω1t)] + Ae^[i(k2x-ω2t)]. Show that particle average velocity Vav = ħ(k1+k2)/2m equals ω2-ω1/k2-k1. Average momentum of the particle is Pav = ħ(k2+k1)/2. Homework Equations p = ħk E=ħω K = 1/2 * mV^2 The Attempt at a Solution...