Average velocity Definition and 279 Threads

I understand that it's possible to have a negative instantaneous velocity, but I'm wondering if it's possible to have an negative average velocity. For example, let's say you start heading north at a constant 10 mph for an hour. The second hour, you drive south (directly toward the starting...

I'm trying to find the average velocity of a spinning propeller. v(r) = RPM C(r) / t ; C(r) = 2πr; t=(1 min) v(r) = RPM 2πr / (1 min) I'm not quite sure what to do next. I need the answer in units of velocity, but if I integrate that last equation, I won't get units of velocity. My rough...

The velocity of a river varies parabolicly with V adjacent to the banks and max velocity d halfway betwee the banks. The flow of river is parallel to the bank. The width of the river is x. How do you calculate the average velocity?

Homework Statement A car traveling at 85km/h strikes a tree. the front end of the car comoresses and the driver comes to rest after traveling 0.8m. Homework Equations a) What was the average acceleration of the driver during the collision? b) Express the answer in terms of g's ; where...

I have been solving these sort of problems, and they follow this basic paradigm: first, they will tell me I traveled a distance D at a velocity of A, then they traveled the same distance D at a velocity of B. Why can't I simply just simply perform the following computation: (A+B)/2. I have been...

I just need some clarification. In a lab that i did, a metal ball goes down a slanted ramp, onto a horizontal ramp of d distance, and then goes airborne (off the table). The instant the ball enters the horizontal ramp a timer is started, and - when it goes airborne - the timer is stopped. Thus...

This question is about a discrepency between the method of finding average velocity via "change in distance over change in time" and the other method of "instantaneous velocity + instantaneous velocity all divided by 2" If I find average velocity of various points on a position vs position...

Is there such a thing as magnitude of average velocity? If so, is it one of these? Suppose I have to position vectors. \stackrel{\rightarrow}{r}= 1_x + 2.2_y and \stackrel{\rightarrow}{r}_2 = 2_x + 0_y And the distance between the vectors is Δ\stackrel{\rightarrow}{r}=...

Homework Statement The position of a particle in meters moving along the x-axis is given by: x=21+22t-6t^2 Calculate the average velocity of the object in m/s during the time interval t=1s to t=3s. Homework Equations x=21+22t-6t^2 t=3 ; t=1 v avg. = Xf - Xi/Tf - Ti = Δx/Δt don't...

Homework Statement A ball is projected upward at time = 0.0 s, from a point on a roof 10 m above the ground. The ball rises, then falls and strikes the ground. The initial velocity of the ball is 98.8 m/s Consider all quantities as positive in the upward direction. The average velocity of...

Homework Statement I am having difficulty thinking about this problem. How is speed related to average velocity? A car travels along a straight line at a constant speed of 47.0 mi/h for a distance d and then another distance d in the same direction at another constant speed. The average...

I'm doing a homework problem (i already know the answer) and i came across an error in my logic/application of the formula Vavg = (v + v0)/2. Hopefully you can help me understand why it's incorrect to use the formula. x = 12t2-2t3 describes a particle position. the derivative of x = 24t-6t2...

Homework Statement A current of 1600A exists in a rectangular (0.4-by-16cm) bus bar. the current is due to free electrons flowing the wire at an average velocity of v meters/second. If the concentration of free electrons is 10^29 electrons per cubic meter and if they are uniformly dispersed...

A question about the average velocity of bodies undergoing one-dimensional motion and a constant acceleration (gravity in this case). A case scenario. Suppose that initially, I throw a stone into the air at a height h. For the sake of argument, let's suppose that even though I threw the...

Homework Statement Shouldn't average velocity multiplied by 2 be equal to final velocity. We were doing a lab and we calculated an average time of .54 seconds to travel 1.92 meters. Multiplying the average velocity by 2 gives an extremely different answer than vf=gt. I know there is...

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 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 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 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...

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 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...

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...

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...

hey guys I am very new to physics and its just not making sense at the moment and i know this is a very simple question but i just don't get how to get the velocity ! I've worked out the average speed but i have no idea what the next step is to get the velocity, any hints would be very much...

Homework Statement A family travels from hither to yon one afternoon. On this day, the driver spends half the distance traveling at 77 km/hr and the remaining half at 50 km/hr. What is the average speed during the trip? Homework Equations The Attempt at a Solution I assumed that...

How does one get the average velocity from a velocity vs. time graph, when acceleration is not constant.

Homework Statement When I looked a physics for a while, I learned that average velocity is the sum of the initial and final velocities divided by two. However, I looked through one of my calculus books and it defined average velocity as the change in displacement over the change in time. Could...

Hi I am trying to work this out, but i just cannot find anything on how to work it out, I need to create this for a project and need to calculate itQuestion A Simple single loop generator, the loop has a length of 40mm and diameter 20mm. The flux density is 0.8 Tesla and the loop rotates at 50...

Homework Statement The velocity of the transverse waves produced by an earthquake is 6.96 km/s, while that of the longitudinal waves is 12.0408 km/s. A seismograph records the arrival of the trans- verse waves 59.4 s after that of the longitudi- nal waves. How far away was the...

A train leaves the train station at 9:00 am and travels at a constant speed of vt = 65 km/hr on a straight track. At 10:30 am, a car leaves the same train station and travels in the same direction at vc = 115 km/hr on a road next to the train track. a.How far from the station is the place...

Homework Statement 1. the average velocity of the air to meet the required volume flow rate, 2. the pressure a fan needs to produce to overcome the frictional losses in the duct, 2. Relevant Information Duct size - 600 mm x 600 mm which operates at 3 Pa/m. The air path is 87 meters from...

Hey quick question regarding the average value of a function; What is the difference in finding the average velocity over an interval given the position function, s(t), and the velocity function, v(t)? I don't get it?

Homework Statement A relay race is run along a straight-line track of length 300.0 m running south to north. The first runner starts at the south end of the track and passes the baton to a teammate at the north end of the track. The second runner races back to the start line and passes the...

Homework Statement Car passes distance x1 with velocity v1 further it passes distance x2 with velocity v2. Find average velocity (averaged by distance), at that consider x1 and x2 as weighting factors. Homework Equations Vaverage=(v1t1+v2t2)/(t1+t2) The Attempt at a Solution I...

A car travels east at 73 km/h for 1.4 h. It then travels 30.0° east of north at 129 km/h for 0.5 h. (a) What is the average speed for the trip? 87.7 km/h (b) What is the average velocity for the trip? Magnitude ____ km/h Direction ____ Homework Equations V avg= delta r/delta...

Homework Statement Homework Equations d = 2.5 c = pi*d = 7.854 velocity/s ?= c * 2 = 15.7079The Attempt at a Solution Since PR is 1/4 of the circle and the particle moves around the circle 2 times per second, I thought the average velocity would be 1/8th of the velocity that it's traveling...

Homework Statement During a race on an oval track a car travels at an average speed of 200km/h. a) How far did it travel in 45.0mins? b) determine its average velocity at the end of its 3rd lap. Homework Equations ok I worked out part a of the question and that is fine. But logically...

Homework Statement A sample of an ideal gas is in a tank of constant volume. The sample absorbs heat energy so that its temperature changes from 304 K to 608 K. If v1 is the average speed of the gas molecules before the absorption of heat and v2 their average speed after the absorption of...

Homework Statement A rocket traveling at 88 m/s is accelerated uniformly to 132 m/s over a 15.0 second interval. What is its average velocity, with the correct number of significant figures? An object traveling at 11.5 m/s is decelerated uniformly to 4.5 m/s. What is its average velocity...

In the photo attached, i have tried to derive the formula that average velocty is equal to the sum of initial and final velocities divided by two. But i am not sure about one step encircled in the photo. I don't know whether encircled step is right or wrong. I have another idea of deriving this...

Homework Statement In reaching her destination, a backpacker walks with an average velocity of 1.21 m/s, due west. This average velocity results because she hikes for 6.44 km with an average velocity of 2.52 m/s, due west, turns around, and hikes with an average velocity of 0.435 m/s, due...

I don't require an answer to the problem itself, but rather a method I can use to solve it: Homework Statement You spot a deer down the road, so you brake to stop before hitting the deer. If your initial speed was 23m/s, what was your average velocity during braking? Deceleration was...

i am new to physics, so could anyone help me solve this problem thank youHomework Statement A cyclist travels 26.7 km in 54 min 16 s. What is his average velocity in m/s?Homework Equations The Attempt at a Solution

Homework Statement Heather and Matthew walk with an average velocity of 0.98m/s eastward. If it takes them 34 min to walk to the store, what is their displacement? Homework Equations V avg = Δx/Δt (since I'm looking for the displacement I changed it to) Δx=V avgΔtThe Attempt at a Solution...

Homework Statement A car travels east at 95 km/h for 1.5 hours. It then travels 30.0° east of north at 111 km/h for 1.8 hours. What is the average velocity for the trip? (Magnitude and degrees)Homework Equations law of cosines/resultant The Attempt at a Solution I have tried doing this...

Homework Statement The velocity v of blood that flows in a blood vessel with radius R and length l at a distance r from the central axis is v(r), where P is the pressure difference between the ends of the vessel and η is the viscosity of the blood. v(r) = P/4nl (R^2 - r^2) a) Find the...

Homework Statement An electron moves in the positive x-direction a distance of 2.44 m in 3.10 *10-8 s, bounces off a moving proton, and then moves in the opposite direction a distance of 1.68 m in 3.53*10-8 s. The Attempt at a Solution to find the average velocity I used the distance...

Homework Statement Homework Equations The Attempt at a Solution I thought it was "D". The correct answer is "A". Can you help me figure out why?