Motion Definition and 999 Threads

Homework Statement Homework Equations displacement = .5(wi+wf)*t wi =0 wf=5 rev / sec t=10 The Attempt at a Solution displacement = 5/2*10= 25 revolutions I know it is simple, but I am not sure if i heard right that the answer is actually 50 revolutions. Did i do something wrong?

Homework Statement Describe three ways that understanding projectile motion and relative velocity could help you improve your success in a basketball game Homework Equations none The Attempt at a Solution 1: Understanding projectile motion and relative velocity helps a basketball player to...

Greetings, I have begun reading the Feynman Lectures to repeat the most important ideas from my undergraduate studies and to improve my intuitive understanding of physics. In one of the first chapters, the one about the conservation of energy, he demonstrates that the conservation of energy is...

Homework Statement Two positive point charges Q are located at points (±l, 0). A particle with positive charge q and mass m is initially located midway between them and is then given a tiny kick. If it is constrained to move along the line joining the two charges Q, show that it undergoes...

I thought this was nice. In what follows, ##c=1##. For a particle undergoing constant proper acceleration ##\alpha## in the positive ##x##-direction, an inertial observer can use: ##x (\tau) = x_0 + \dfrac{\gamma(\tau) - \gamma_0}{\alpha}##, where the Lorentz factor is: ##\gamma (\tau) =...

Homework Statement Homework Equations ##\tau = rFsin(\theta)## ##\tau_{net} = I\alpha## ##F = -kx## ##kx = mg## The Attempt at a Solution I don't understand how the restoring force from the bending of the ruler behaves (so I have no idea how to apply torque here). I also don't understand how...

Homework Statement The initial speed of a ball up an inclined plane is 3 m/s upwards. The ball reaches its highest point after 1.2 seconds. a) find the acceleration. b) how far has the ball gotten during this time? c) how far has the ball rolled after 0.4 s and after 2.4 seconds? Homework...

If friction is independent of area of contact, how do less inflated tires of a bicycle experience more resistance towards motion than the well inflated tires?

One thing I don't understand is that How Amplitude is conserved on both sides if the mass is subjected to different forces on either side of this shm...

Homework Statement (For this problem ignore the height of the firefighter) A firefighter, a distance (d) from a building, shoots a stream of water at an initial angle, above the horizontal, at initial speed (Vo). At what height (h) does the water strike the building? No values were given to...

Hello guys, and sorry for my english in advance. I was presented some time ago with the following problem: Suppose there is a frog that jumps in any direction randomly, and all the jumps have size 1. What's the probability of, after 3 jumps, the frog be less than 1 unit from the origin. I...

Homework Statement I need to come up with an equation that would model the motion of a non-linear pendulum with air resistance. [/B]Homework Equations Fc=mgsintheta Fdrag=(1/2)p(v^2)CA The Attempt at a Solution I started with mgsintheta-(1/2)p(v^2)CA=ma After substituting v=r*omega and...

Hello, I understand that Newton's laws of motion can explain how a hummingbird is able to hover in front of flowers. There is one question I have in particular, which is, Is the lift generated by the wings of the bird and its weight force an example of a pair of Newton's third law forces? They...

I'm taking physics for the first time, and I've been attempting the textbook problems, but I can't seem to get it. 1. West stands on the roof of a building, leans over the edge and drops a rock. Lindsay waits 1.25 s after West releases his rock and throws her own rock straight down at 28.0...

Homework Statement A partice is projected at an angle 60 degrees with the speed 10 m/s. Then latus rectum is ? g= 10 m /s^2 Homework Equations i calculated the maximum height.Now what?? The Attempt at a Solution h= u u sin theta sin theta/2g

Homework Statement A simple harmonic oscillator, with oscillations in the x direction, has velocity given by: $$v_{x} = (2.2 \frac {\mathrm{m}} {\mathrm{s}}) \sin [(6.9 \frac {\mathrm{rad}} {\mathrm{s}}) t]$$. Find the values of ##\omega , A, f , T ,## and ##\phi## Homework Equations $$v_{x} =...

Homework Statement A perfectly solid marble of radius R rolls without slipping at the bottom of a spherical bowl of a radius 6R. The marble rolls back and forth in the vertical plane executing simple harmonic motion close to the lowest point. How long does it take the marble to go down one side...

If we have a system of masses in motion, will the velocity of the center of mass always be given by the net momentum divided by (1/c^2 times) the total energy of the system?

Homework Statement The equation y = A sin(kx - wt + pi/2) is the same as a. y = -A sin(kx - wt + pi/2) b. y = A cos(kx - wt) c. y = -A cos(kx - wt) d. y = -A sin(kx - wt - pi/2) e. y = A sin(kx - wt + (3pi)/2) Homework Equations y = A sin[(2pi)/lamda * x - (2pi)/period * t + (phase constant)]...

Homework Statement :[/B] Say for example I've got the equation of a SHM as: $$x = A \cos (\omega t + \phi)$$ where ##A## is the amplitude. How do I find the time period of this motion? Homework Equations :[/B] Stated above. The Attempt at a Solution :[/B] I tried by finding the second...

Homework Statement On a plane tilted at the angle of 30 degrees with the horizon lies an object, whose weight is equal to 1.4 kg. The coefficient of friction between the object and the plane is equal to 0.2. Find acceleration. m = 1,4kg; (weight) Angle (A) = 30 degrees. COF µ = 0,2 Ff -...

Homework Statement Consider a solid spinning sphere of negative charge in a non-uniform magnetic field: http://d2vlcm61l7u1fs.cloudfront.net/media%2F2f8%2F2f840122-3d7f-4af3-98a7-efa9b2e7d26a%2FphpBOhfaK.png (the rotation illustrated at the top is supposed to be counter-clockwise). What...

I am to try to find simple way to spin a spinning flywheel. What linear motion device acting on the outside edge of a spinning flywheel can be used to increase the speed of the flywheel. Need to use a repeating pattern such as pushing your hand down over and over on the edge of the wheel to...

I am having trouble understanding tangential speed as it applies to uniform circular motion and I would appreciate any help. Say I have a ball on the end of a string that I hold with my hand and rotate at a constant speed. If the string provides the centripetal force and acceleration, where...

Homework Statement the cone of a loudspeaker vibrates in SHM at frequecy of 262Hz. the amplitude at the center of the cone is A=1.5X10^-4m and t=0 and x=A (amplitude). 1) what equation describes the motion of the center of the cone ? 2) what are the velocity and acceleration as a function of...

Homework Statement We have an object rotating inside a circular container. The rotation is vertical (see picture below). The radius r of the container is given. Find the frequency (which then ties back to finding the centripetal acceleration) necessary, so that the objects rotating inside the...

Homework Statement Keys with a combined mass of 0.100 kg are attached to a 0.25 m long string and swung in a circle in the verical plane. a) What is the slowest speed that the keys can swing and still maintain a circular path? b) What is the tension in the string at the bottom of the circle...

Hi all, I recently learned the concept of Maxwell's speed distribution and became interested in how to use similar momentum distributions to study the probabilistic motion of a classical free particle. I have done some of my own reading on probabilities and distributions (no formal lessons yet)...

Hello ladies and gentlemen I am working on a Unity 3d game project and I am in need of some physics guidance. You probably know Unity3d has a built in physics engine, and if you don't you do now. :) I am determined to figure this out more or less on my own but I need some assistance with the...

I have some questions and refer you to the image below the caption of which states, "D-branes may be of exceptional importance in the explanation of elementary particles of the Standard Model. However, it still remains to find a solid connection between the M-theory and the Standard Model."...

Homework Statement An object of mass m = 1 kg moves along a circular frictionless path of radius R = 0.5 m from point A to point B at which it makes an angle θ with the vertical direction as shown in the figure. If the object is release from rest (VA = 0) and θ = 30° , what is the normal force...

Hey this is just a random question, but recently I've started studying physics, only last year. Before this I never used to question really a lot of things i took for granted, but now I see the world with a different light although I'm still quite the novice. Something that used to make me...

Hi, I had a thought recently which gave rise to a rather interesting query. A helicopter works and is able to fly due to Newton's third law of motion. The propellers rotate at a high speed and exert a force on the air beneath them. By N3L, the air therefore exerts an upwards force on the...

Homework Statement Homework Equations [/B] Equations of motion: v = u + at s = 1/2 (u + v) t s = ut + 1/2at^2 v^2 = u^2 + 2as 3. The Attempt at a Solution Hello, on a i used the 2nd equation: 30m = 1/2 (3*10^8m/s+3*10^8m/s) t so -> t = 1*10^-7s but to get the correct solution i...

Homework Statement Referring to the attached diagram, the object ABCD is kept in an isolated system where it is under no external influence of any kind. A· An instantaneous force F acts along the edge BC of the block ABCD, where M is its mass, with its center of mass located at O...

Homework Statement from the lagrangian density of the form : $$L= -\frac{1}{2} (\partial_m b^m)^2 - \frac{M^2}{2}b^m b_m$$ derive the equation of motion. Then show that the field $$F=\partial_m b^m $$ justify the Klein_Gordon eq.of motion. Homework Equations bm is real. The Attempt at a...

If two objects are traveling on paths at 90 deg to each other such that they will converge at a point how do we describe that motion. For example 2 cars are approaching a 4 way intersection and will collide. They see each other as moving diagonally yet when they collide one will t-bone the...

We consider a monoatomic gas in a closed box. A textbook says : Since the assumption is that the particles move in random directions, the average value of velocity squared along each direction must be same. Why the assumption is that the particles move in random directions implies that the...

Homework Statement "A ball thrown straight up with an initial speed of 30/m/s. (a) Show the time it takes to reach its trajectory will be 3m/s (b) Show that it will reach a height of 45m" Homework Equations h=ut+1/2g^2 1/2gt^2 The Attempt at a Solution Part a of the question I am fine with...

I have a spring with mass M attached, and leave it at equilibrium. Then I displace it some more by stretching it down a bit more. Displacement due to the mass= X, displacement due to stretching it even more=Y. Why isn't the amplitude of oscillation= X+Y, but is only actually only Y? This is...

Homework Statement Hello, I am trying to find the equations of motion that come from the fermi lagrangian density of the covariant formalism of Electeomagnetism.Homework Equations The form of the L. density is: $$L=-\frac{1}{2} (\partial_n A_m)(\partial^n A^m) - \frac{1}{c} J_m A^m$$ where J...

What types of objects does Newtonian mechanics deal with? Is it just rigid bodies? I’m not sure how Newton’s laws could explain something like the motion of a wiggling rope.

Homework Statement l=2m b=1.5m The mass of the chair is 5kg. A boy with a mass of 50kg sits on the chair. The distance of the chair from the pole is 3m, and it spins around it horizontally with a radial velocity of 1.95 rad/s. The boy drops a ball at some moment, what would be its distance...

Homework Statement A 1200 kg car has a speed of 5 m/s at the top of a circular ramp of 10 m in radius. The normal force exerted by the seat of the ramp on the car is : A) 9000N B) 9600 N C)11250 N D)13650 N E)14150 N Homework Equations ∑F=ma ac = m v^2 /r The Attempt at a Solution...

Homework Statement A mass m, at one end of a string of length L, rotates in a vertical circle just fast enough to prevent the string from going slack at the top of the circle. Assuming mechanical energy is conserved, the tension in the string at the bottom of the circle is: a) 6 mg b) mg +...

Homework Statement I'm having trouble with part A of this question 1. A ball is fired out at an angle of 30° from the platform of height h = 0.5 m as shown in Figure 1. It is subjected to the gravitational force only thus follows a projectile motion. It falls onto the ground after 0.6...

Homework Statement A student can throw a football a max range of 60 meters. How far could he throw it if the Earth's gravity were reducted to 1/6 of its normal value , similar to the moon's gravity? Homework Equations v = .5at^2 The Attempt at a Solution I feel like i did this wrong but x =...

I shall try to expose my question as briefly and clearly as possible. Within a very old and classical approach (Newton), discussions take place in a three-dimensional Euclidean space and the concept of force is represented by a vector which is proportional to the mass of the object at hand (m...

A mass m = 0.15 kg is attached to a massless string and rotates at constant speed v = 4 m/s in a horizontal circle of radius 2 m. The tension T (in N) in the string is: (a) 1.1 (b) 1.9 (c) 2.4 (d) 3.3 (e) 4.9 I would assume that first I calculate the centripetal acceleration by using v^2/r =...

Homework Statement An object of mass m is rotating, hanging from a string of known length l. The string is attached to a pole, which rotates with a known angular velocity ω and forms a to-be-determined angle α with the string. Find α. I think I have solved it (the numbers match the results of...