Constant velocity Definition and 199 Threads

Homework Statement So I'm confused about work and constant velocity. In a sailboat example, if the boat is going at constant velocity then there is no acceleration, therefore no net Force and no work. However, let's say there is an elevator being pulled upward by a pulley at constant...

Hey guys, I really don't know how approach this easy physics problem. You have a turtle and a rabbit. Constant speed of turtle is 0.2m/s of the rabbit 8 m/s. They both compete over a distance of 1 km. At 0.8 km the rabbit stops to teaste the turtle. How close to the goal can the rabbit let...

Homework Statement Speedy tortoise can run 10cm/s, and a hare can run 20 times as fast. In a race, they both start at the same time, but the hare stops to rest for 2 minutes. The tortoise wins the race by a shell (20cm). A)How long does the race take? B)What is the length of the race...

New guy here with a question about Special Relativity and stopping acceleration. Forgive me if I have any of this wrong. I'm generally unable to follow physics for a long time before getting lost (I'm very right-brained--which means I'm artsy, not mathematical--and I've been told my brain can't...

Homework Statement A climber of mass 64.8 kg is rappelling down a cliff, but has momentarily paused. She stands with her feet pressed against the icy, frictionless rock face and her body horizontal. A rope of negligible mass is attached to her near her waist, 1.04 m horizontally from the rock...

Homework Statement A 1.0 kg object, moving with a constant velocity of 2.0 m/s, is acted upon by a force of 15 N in the direction of the motion for 6.0 s. What is the velocity (in meters/second) of the object at the end of this time? Homework Equations I was thinking of using, V = Vo...

Here an AP Physics problem that's really bugging me. Homework Statement A particle moves along the parabola with equation y = .5x^2 part a) I believe I did this correct. part b) Suppose that the particle moves with a velocity whose x-component is given by vx = c / (1 + x^2)^.5 Show that...

I am doing make-up questions from my General Physics test. This is pretty easy stuff, and I thought I answered correctly, but according to my teacher's comments on my paper it seems like I'm missing something. Homework Statement For the data provided, is the velocity for this object...

Homework Statement A car of mas m = 1000kg is sliding down a hill. The coefficients of friction between the car's tires and the ground are us=0.89 and uk=0.61. For what inclination angle will the car slide down the hill with a constant velocity? Homework Equations The Attempt at a...

Hi All. This is my first post, so please forgive me if I am not following protocol somewhere. The question: A mass flows through a let's say a pipe with a rectangular cross section at a constant velocity. I am just trying to figure out all the forces acting on this mass. Of course the...

Hi guys, I am self-studying physics, but I am confused for something following: given 1-d motion of an object o, we can use these equations to describe the motion of it. \overline{v} is a constant, so is\overline{a} . 1)x_t=x_0+\overline{v}t 2)v_t=v_0+\overline{a}t...

Hi guys, I'm reallyyyy stuck on this so I would really appreciate your help, cheers :) 2. Particle P passes through posiion A (12,3) with constant velocity i + 2j m/s. At the same time Particle Q passes through position B (3,-3) with c.v 2.5i + 3j m/s. Find the position vectors of P...

A point charge is moving at 1 x 10^6 meters per second. At the origin (0,0), a magnetic field of 1 T is applied into the page. The charge = 1.6 x 10^/10 C. 1) Calculate the force. 2) Calculate the exact location it hits the X intercept. 3) Calculate the time is takes to hit the X intercept...

If a something is rotating about an axis with a constant velocity is the sum of the acting moments 0 since no acceleration is occurring? Moment = mass x acceleration x distance If acceleration is 0, the moment is 0. Is this correct?

We know that light propagates in a constant speed c, but what if we are moving in an air plane and then turning on the light, why the speed of light remains constant?... Thank u.

A sled is pulled 3 meters at constant velocity up a 20 degree incline. the efficiency of this procedure is 42%. Calculate the coefficient of friction between the crate and the incline. alright I'm completely clueless on this one. i know that efficiency=output (energy delivered by...

Hi there. This problem is very basic but I really cannot figure out how to solve it. I'm missing something but I have no clue what it is. Homework Statement Three forces act on a moving object. One force has a magnitude of 80.0 N and is directed due north. Another has a magnitude of 60.0 N and...

Homework Statement When you are 20m away from your bus it begins accelerating at 3 m/s/s (from rest). With what constant velocity should you run at to catch the bus? Homework Equations v-u=at s=ut+\frac{1}{2}at^{2} v^{2}=u^{2}+2as The Attempt at a Solution I've done loads of...

7. Q: "If you must average 60 km/h for a 90 km trip, and you only average 40 km/h for the first 40 km, what velocity must you average the rest of the way?" A: 90 km 60km/h 1.5h d v t 1st 40 km 40 km/s 1h d v t 2nd 50 km ...

5. Q: "A boat crosses a 2.85 km lake in 28 min. Find it's average velocity". A: We want the answer in m/s, so I have to convert km to m, and min to s, right? Now I know how to do that, but not in the calculative way. I know that there is 1000 m in one km, so I multiplied 85 by 1000 and got 85...

Homework Statement A man lifts a 2.2 kg stone vertically with his hand at a constant velocity of 1.5 m/s. What is the force exerted by his hand on the stone? Homework Equations F=ma (I would assume) The Attempt at a Solution I know that (9.81 m/s^2)x(2.2 kg) = 21.582 N (the...

Does time dilation occur when an object is moving at a constant velocity and not accerating?

Homework Statement Kind of wordy, please bear with me: A hare and a tortoise compete in a rase over a course 1.00 km long. The tortoise crawls straight at its maximum speed of 0.200m/s. The hare runs 8.00m/s for 0.800 km and stops to tease the tortoise. How close to the goal can the...

Let a bicycle run straight on a plane past you from left to right with constant speed. As a representative point of the bicycle take the center of the back axle. Since the bicycle has constant speed with regard to the plane, so has the axle (trivial). In addition a point on the rim of the wheel...

Homework Statement A tanker ship with a mass of 10000Kg is moving with constant velocity into a harbour. Two tugboats interact with the front of the boat with a net force of 10464KN, what acceleration does it undergo? Homework Equations a=F/m The Attempt at a Solution...

Hi all! I am required to find the velocity distribution of the flow around an infinite plate that suddenly starts moving with a constant speed U_o. The solution has already been worked out, but I still do not understand all of it. The part that is perplexing to me is where they use the...

I have attached two very simple problems with their solutions. In the first problem the velocity of the mass center is not constant while in the second it is. From my understanding, the mass center of a object that explodes continues to move as if the object had not exploded and if there are...

Homework Statement At a certain part of your drive from home to school, your car (mass m) will coast in neutral at a constant speed of v if there is no wind. Examination of a topographical map shows that for this stretch of straight highway the elevation decreases an amount h for each segment...

"A child rides a wagon down a street with an inclination angle of 38.0 degrees. In order to keep from moving to fast, the child has secured the wheels of the wagon so that they do not turn. The wagon and the child then slide down the hill at constant velocity. What is the coefficient of kinetic...

having trouble setting these style of problems up. please take a look. problem: A student it running at a constant velocity of 6.00m/s to catch the campus shuttle bus, which is stopped at the bus stop. When the student is 80 m from the bus, it starts to pull away with a constant acceleration...

An 1520 kg car is moving to the right at a constant velocity of 2.94 m/s. (a) What is the net force on the car? (b) What would be the net force on the car if it were moving to the left? any help i tried using Force=Mass*Acceleration I also don't know what it wants me to dod when...

car moving at a constant velocity...and many other questions on KE This is NOT hw...just a semantics inquiry. Say you have a car moving at a constant velocity. Is the engine doing work on the object since it is exerting a force on the car in the direction of the motion? I am thinking...

Question: Which of the following statements could be true? a) A car moves with a constant speed around a circular track. b)A car moves with a constant velocity around a circular track. This is question #2 from the kinmatics quiz link on this forum. It marked me wrong for...

i have confuse and can't understand what is the defination and equation for constant velocity and constant acce. Anybody pls help to explain to me pls... thanx...

Derive the slope of a track where a sphere having frictional coefficient u maintains constant velocity v.

Hi, I've got a big probllem: When you are 20m away from your bus it begins accelerating a 3m/s/s (from rest). What constant velocity should you run at to catch the bus. HELP! Please! jason

Ok, I already posted this a few days ago but I am bringing it back because i don't quite understand a man sits in a bosuns chair that dangles from a massless rope, which runs over a massless frictionless pulley, and back down to the mans hand. The combined mass of the man and the chair is...

Im having trouble with a part of a problem. The problem is: There is an elevator with a mass of 1200kg accelrating upward at 2.1m/s^2. Find T. For that what I did was 1200 \times 9.8m/s^2 which gave me 11,760. I then plugged this into F=ma and got 14,280. The second part of the equation...

The question is the title.

Q. An object starts at time t = 0 with a velocity of v0 = + 21 m/s and undergoes a constant acceleration of a = -5 m/s^2. a) How far from its starting ( t = 0 ) is the object at time at which it comes to rest? Solution: Since, the object undergoes constant acc. constant acceleration...

I've been working on this problem all afternoon and i just have a complete blackout and no idea how to solve it: the question is what force, parallel to the plane has to be applied if the object is moving up an inclined speed at a steady speed of 3.2 m/s. i have the object's mass and the angle...

The SI units for force is kg*m/s^2. So, if a object travels a certain distance with no acceleration, because it has a constant velocity. What is the force? Is it correct to find the KE, which units are kg*m^2/s^2 and divide the distance? Also, KE is the energy from motion, correct? So, is...

Are we more likely to be able to walk at constant velocity or at constant acceleration?

Hey there, I have a problem that seems easy to me to solve but I'm just not getting it. I'll give the problem and then what I've done so far. A helicopter is moving horisontally to the right at a constant velocity. The weight of the helicopter is W = 51200N. The lift force L generated by...

can someone tell me what these formulas do? constant velocity(when velocity is constant, which is 0 right?, you use these formulas)... 1.) a(t) = 0 <== when constant velocity, a(t) = 0 right? 2.) v(t) = Vi(what is v(t)? vi = initial) 3.) x(t) = Xi + ViT (what is this formula used for...

How do I use Kinematic equation with constant velocity. I only have used with intital and final velocity. A parachute dropped from a 30-meter-high cliff falls with a constant velocity of 1.5 meters per second. Twenty-two seconds later a stone is dropped from the cliff. a. How long...

Hello all. Great site here. I have been working on this problem for a while now and I cannot figure out the magnitude of the force. Pam, wearing a rocket pack, stands on frictionless ice. She has a mass of 45 kg. The rocket supplies a constant force for 22.0 m, and Pam acquires a speed of...

Does the speed of a block of wood being pulled across a surface go twice as fast if you pull twice as hard? If yes/no, why? Thanks to anyone who will answer that!

Hi All, It is Experimentally very evident that the speed of light in any any frame of reference is constant. But is there any explanation for why this happens. Velocity of light seems to be like zero in mathematics. Any thing multiplied my zero results in zero irrespective of the number...