Average Definition and 1000 Threads

A man runs up 1576 steps in 9minutes 33sec. If the height gain of each step was 0.20m, and the mass of the runner was 70.0kgs, what was average power output during climb? I used P=W/T & W=FD W=70kg(1576)0.20=22,064J P= 22,064J/573s = 38.5 W answer given is380W What am I missing?

Homework Statement I have to compute the average of A in all directions for a sphere of radius R. For the direction r, A is defined as: A=\int_0^R n(r)dr where n(r) is the density profile of the sphere. The answer should be \langle A\rangle=\frac{4}{3}\left\langle n \right\rangle R 2. The...

A CD has a playing time of 74.2 minutes. When the music starts, the CD is rotating at an angular speed of 488 revolutions per minute (rpm). At the end of the music, the CD is rotating at 215 rpm. Find the magnitude of the average angular acceleration of the CD. Express your answer in rad/s^2...

Homework Statement My question pertains to taking the average over a particular period that is composed of 2 functions. For example, from [0, 5ms] the function is defined by 1-e^(-t/1ms)and then by e^(-t/1ms) from [5ms, 10ms]. Will the average from 0-->10 simply be the following...

Homework Statement http://img440.imageshack.us/img440/9242/captureyeq.jpg Uploaded with ImageShack.us Homework Equations Given in problem statement. The Attempt at a Solution Basically I've come up with the contrapositive, but I'm unsure of how to proceed with the proof. Can...

Dear all, Although the following question involves some terms using finance, I post it here since it seems to involve some probability. I hope that it will be fine. Thank you very much for your help. --------------------- Problem: Suppose that John buys shares in only one company...

What is the average of (Ri-1/N*Sum[Ri])^2 The sum is from i=1 to i=N.

Homework Statement Hey guys. Hope you can help me out on this one. so here's the question: At an altitude of 50km the average atmospheric temperature is 0^oC. What is the average number of air molecules per cubic centimeter at this altitude. Homework Equations M = 28.97 g mol^-1...

Homework Statement Find the average value of the function u(x)= 10xsin(x2) on the interval [0, ∏1/2] (Sorry, I can't figure out how to make the square root symbol)Homework Equations The Attempt at a Solution For the integral of u(x), I got -5cos(x2) I substituted 0 and ∏1/2 and got 10. then...

Is average velocity equal to the average of two instantaneous velocities. I had a question on a calculus exam that gave an equation to a particle moving and was told to find both the average velocity on the time interval [0,1] and the instantaneous velocity at 1. I took the derivative of the...

Homework Statement Two girls are arguing about which is able to hit a hockey ball harder. Describe an experiment which they could carry out to measure the average force between the stick and ball during time of contact. Homework Equations Force * Time=Change in Momemtum (Mv-Mu) The...

I have to deliver this problem resolved in 4 hours, I didn't think it was going to be so hard... Homework Statement A man of mass M is on the top of a balance with a very high damping coefficient. In a given instant he throws a ball of mass m vertically, catching it again later. a)...

When a stars radial velocity is measured in search for a planet, the planet imparts a radial velocity shift proportional to m\sin i\text{ where }i is the orbital inclination of the planet with respect to our line of sight and m is the planet mass. I've heard that even though the inclinations are...

Homework Statement mass of a car is 2000 kg that can go from 0-120 km/h in 3.5 seconds. What is the average power? Homework Equations I know that the average power is Work/time, or (force * displacement)/time = F*average velocity. My only question is how to find the force of the car...

So I am currently in an average ABET EE program and have a 4.0, but I am thinking of transferring to the top 30 engineering school about an hour away. I was wondering which matters more, GPA or institution? Both have a great college fair, and both are ABET accredited. And, I am not saying I...

I haven't done anything Physics related in 2 years (high school) and am trying to get back into being familiar with Physics, Science, and mathematical terms for an upcoming class. Homework Statement A gazelle starts from rest and runs in a straight line 29° north of west. After 36s of...

Homework Statement A ball is thrown into the air a velocity of 49 ft/s. Its height in feet after t seconds is given by y=49t-10t^2. A. Find the average velocity for the time period beginning when t=3 and lasting 0.01 s: 0.005 s: B. Estimate the instantaneous velocity when t=3.Homework...

Homework Statement Find the average value of : f(x) = 4sinx + 4cosx on the interval [0, 16pi/6] Average value: ? Homework Equations Integrals The Attempt at a Solution 1/ [(16pi/6) -0] ∫ from 0 to 16pi/6 4sinx + 4cosx dx [3/8pi] ∫ from 0 to 16pi/6 4sinx + 4cosx dx <------simplify...

If the average rate of change of a function f over the interval from x = 2 to x= 2 + h is given by 7e^h -4cos(2h), then f ' (2) = ? This is what I got: [f(2 + h) - f(h)]/h = 7e^h -4cos(2h) I know we are supposed to used Mean-Value Theorem, I just don't get how to do it.

Homework Statement An object moves along a circular path with a constant speed, |v|. The average acceleration in going from A to B is 1. south 2. zero 3. west 4. north 5. east 6. none of the others Homework Equations a = Δv / Δt tangential acceleration = mv^2 / r...

1. An electric train initially moving at 25km/h accelerates to 35km/h in 20s. Find its average acceleration in m/s^2. G: v1 = 25km/h v2 = 35km/h Delta t = 20s R: Aav 2. Aav=(v2-v1)/delta t 3. = (35km/h-25km/h)-20s The problem is that the velocities are in km per...

Homework Statement Link of picture that the information below is referring to: http://i56.tinypic.com/283lv.jpg You encounter the sedimentary rock outcrop shown above while you are out hiking. You collect rock samples from points A-D and go back and measure their ages in your isotope lab...

Homework Statement A car is initial at rest. It accelerates over a distance of 1250m and reaches a speed of 112 km/h. Find: A) the acceleration for the car B) the time it took for it to reach this final speed C) the average speed Homework Equations A = delta V/ delta T or v^2 = V...

Homework Statement Hi i need some help with this question: A teacher drives to work at a average velocity of 80km/h. He forgets the test and INSTANTLY turns around and travels back home at 120km/h. What is the average speed for the trip? Do i have to find instantaneous velocity? I am not...

Homework Statement An object moves with velocity v(t) = −t2 +1 feet per second between t = 0 and t = 2. Find the average velocity and the average speed of the object between t = 0 and t = 2 Homework Equations \frac{1}{b-a} \int_a^b f'(x) dx avg value of a function The Attempt...

Homework Statement A 0.25 kg ball, initially at rest, is hit with a bat in the x-direction while held 1.00 meter above the ground. If the ball hits the ground 20 meters away and was in contact with the bat for 0.10 sec, What average force was exerted on the ball during the contact time...

Homework Statement a hiker walks 6.7 miles to the east in 5.1 hours. then turns around and walks 1.1 miles to the west in 1 hour. what was her average velocity during the trip? A 1.2mph B 1.3mph C .92mph D 3.9mph Homework Equations not sure how to write what i used The Attempt...

[b]1. A ball is dropeed from a height of 2.5m and rebounds to a height of 2.1m. If the ball is in contact with the floor for .70ms determine 1: direction and 2: the magnitude of the balls average acceleration due to the floor I know the equation for average acceleration = change in...

Homework Statement A racing team of 3 drivers drove a 24 hour event in shifts. The first driver drove only one fourth of the race but averaged 140km/hr. The second driver drove one third of the race at an average speed of 170 km/hr. The last driver drove the remainder of the race at 160...

I just want to know what is the difference on how to find Average velocity and Average speed when I try to find it in Velocity-Time graphs Also how do you find distance traveled and displacement in these velocity-time graphs. Thanks in advance for your help. Please use fairly simple...

Homework Statement A 8.0×10−2 kg arrow hits the target at 25 m/s and penetrates 3.8 cm before stopping. Homework Equations What average force did the target exert on the arrow? What average force did the arrow exert on the target? The Attempt at a Solution I found the...

Though this might be absurd, I would seriously like to know the average magnetic dipole of a magnet. For example, you might consider a regular magnet in a remote control car's motors, or any other suggestions too. And I have one more doubt- I know that e.m.f=-d(phi)/dt and phi=integral(B.dS)...

Homework Statement A car travels east at 86 km/h for 6 h. It then travels 50.0° east of north at 112 km/h for 6 h. (a) What is the average speed for the trip? How do I solve for the average speed?

Homework Statement The given data is a graph depicting the distance (km) that a bus travels over 3.5 hours. The trip is broken up into three linear segments. I am supposed to find the average acceleration over the entire trip in km/hr^2. I am told that the answer will be negative. Edit...

Homework Statement Hello, this is not actually a homework problem. I just can't seem to understand the derivation of the average translational kinetic energy of a molecule. I am startled by the way the velocities are added. Homework Equations My undergraduate level textbook says...

Homework Statement A car is stopped at a traffic light. It then travels along a straight road so that its distance from the light is given by x(t) = bt^2 - ct^3, where b = 2.40 m/s^2 and c = 0.100 m/s^3. 1. Calculate the average velocity of the car for the time interval t = 0 to t = 10.0...

Not sure if this is where this question belongs because the course I am doing is predominately calculus based (Applied Physics, University level) but we have a small statistics component for obvious reasons. Any who, sorry if it's in the wrong spot. Homework Statement Intravenous fluid bags...

Homework Statement I don't know how to start.. someone please give me a step-by-step explanation. Julie drives 100 mi to Grandmother's house. On the way there she drives half of the distance at 42 mi/hr and half the distance at 68 mi/hr. What is Julie's average speed (in mi/hr) on the way to...

Homework Statement Larry leaves home at 9:01 and runs at constant speed 400.0 yards due west to a lamppost. He reaches the lamppost at 9:06, immediately turns and runs due east 1000.0 yards to a tree. Larry arrives at the tree at 9:11. What is Larry's average velocity (in yd/min) for the...

Hi peeps, i just started intro physics but finding it sort of difficult, and attempting to do some questions but just not quite sure if I am doing it right. would so appreciate any kind of help, my teacher doesn't seem to break it down enough for me lol. can somebody just check my work, and let...

A 49.0-g Super Ball traveling at 27.0 m/s bounces off a brick wall and rebounds at 19.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 3.65 ms, what is the magnitude of the average acceleration of the ball during this time interval? I converted 3.65...

Homework Statement A commuting student leaves home and drives to school at an average speed of 42.0 km/h. After 22.0 min she realizes that she has forgotten her homework and returns home to get it at the same average speed. It takes 8.0 min to find the report, after which the trip to school...

Homework Statement What is the average velocity of a runner whose 400 meter lap times are 60, 75, 65 and 60 seconds over a 1500 meter race? Homework Equations The Attempt at a Solution Is I use v=d/t (would the displacement be 0m beacuse he completed 1 lap? Im a bit...

Hi, I'm trying to resolve a problem (17-2) of Pauling's book (Introduction to Quantum Mechanics ), but I'm not achieving this integration. So, I ask for your help. The problem says: Calculate \overline{p_{z}²} (where p_{z} = momentum in z direction and \overline{x} = average value of x...

Homework Statement At t = 0, an automobile traveling north begins to make a turn. It follows one-quarter of the arc of a circle of radius 10.5 m until, at t = 1.42 s, it is traveling east. The car does not alter its speed during the turn. Find the car's speed. Find the change in it's velocity...

A honeybee leaves the hive, flies in a straight line to a flower 6 km away in 10 min, and then takes 10 minutes to return (also in a straight line). a.) Please find the distance traveled and displacement for the entire trip: distance travelled: I know the distance total is 12 km...

I'm having trouble differentiating between the definition of average in physics and a traditional average. For example, say a car travels 100km for 2 hours then travels 80km for 1 hour. The average speed for the first portion is 50km/hr and the average speed for the second portion is 80km/hr...

For the following data set of eight values, give the MEAN, DEVIATION (DEV), and AVERAGE DEVIATION (AD). Show a sample calculation for each: 0.77, 0.92, 1.12, 1.00, 0.96, 0.88, 1.16, 1.02 Homework Equations Well before we began, can anyone take the courtesy and see if I'm getting the...

Homework Statement Is it possible to have zero average speed but nonzero average velocity? Homework Equations The Attempt at a Solution This is probably completely wrong, but I'll put it up anyway: If one's frame of reference is also the center of an arbitrary circle, then an...

An Olympic sprinter can accelerate from rest out of the blocks to a top speed of about 11.5 m/s. This is accomplished in the first 15 m of a race. What is the average acceleration of the first sprinter? Given- vi- 11.5 m/s Distance-15m Vf-? t-? Which formula do I use to find these...