Conceptual Definition and 844 Threads

If a car is traveling at a constant speed up a hill, do you feel lighter, heavier, or the same Can an object have increasing velocity and decreasing acceleration

Question 1: I was told here that in Case A, the torque is equal to zero. I'm not really seeing that. I know torque is equal to rFsin\theta. If I draw a vector from the rotation point (the very center of the spool) to the point where the force is being applied, I get that the force and r...

so i understand how to resolve a limit at x->oo, but from a conceptual standpoint, i do not get it. for example, limit x->oo, 4x/5x so the answer is 4/5, but oo/oo is an indeterminate expression i understand that if i treat x as a variable, then it makes sense, but still if the example was...

Homework Statement Two batteries that have emfs E1 and E2 and internal resistances r1 and r2 are connected in parallel. Prove that if a resistor of resistance R is connected in parallel with combination, the optimal load resistance (the value of R at which maximum power is delivered) is given...

Homework Statement An object is moving to the right in a straight line. The net force acting on the object is also directed to the right, but the magnitude of the force is decreasing with time. The object will a) stop and then begin moving to the left. b) continue to move to the right...

Homework Statement This is conceptual question...Is work a scalar or vector quantity? Is it force times distance or displacement? And it just Fdcostheta by definition of the dot product. Why is it cos theta even when you calculate work done by gravity? Homework Equations Fdcos theta...

When a board with a box on it is slowly tilted to larger and larger angle, common experience shows that the box will at some point "break loose" and start to accelerate down the board. The box begins to slide once the component of gravity acting parallel to the board equals the force of...

I've been wrestling with this problem for a while, and I really cannot understand it. As I understand it, the limit of the resolving power of the eye is related to diffraction: when Rayleigh's criterion is just satisfied, then two objects which are close together can just be resolved, i.e. we...

For years I have been wondering why wind turbines are designed with very skinny blades (photo http://en.wikipedia.org/wiki/File:Turbine_aalborg.jpg ). Most of the available wind passes right through the circular "reach" of the device without touching the blades. Wouldn't it be more efficient if...

Please answer as many as possible! Thanks! 1. If the kinetic energy of a particle is zero, what is its linear momentum? 2. If the speed of a particle is doubled, by what factor is its momentum changed? By what factor is its kinetic energy changed? 3. If two particles have equal kinetic...

Homework Statement If the projectile is launched and lands at the same level. Then the angle is the same at launch and landing, correct? And if the projectile is launched from a different height, then the angle of launch is different than the angle of landing? In such a situation, if it says...

Homework Statement A parallel-plate capacitor consists of two square plates, size L x L, separated by distance d. The plates are given charge +-Q . Each part changes only one quantity; the other quantities have their initial values. Part A What is the ratio E(final)/E(initial) of the...

Since I only got 1 reply on my old post (I think it is because my format is wrong) I am making a new post. Hopefully that is okay Homework Statement a) Person A and Person B are around the same size, they play tug of war. Both pull as hard as they can but none are winning. Compare...

Hey guys, I have a few questions about my physics homework. They are mainly conceptual and I have attempted them. I will write down the questions AND my attempts and please correct me if I am wrong. 1. In a situation of tug-of-war with a friend who is the same size and weight. You both pull...

I am working on a lab, and *think* I understand what is going on, but looking for a double check of my logic from someone more experience than I am. In short its a multi-piezometric tube venturi meter, with 1 throat near the begining, a couple of expansions, and a control valve near the end...

You let an empty suitcase swing to and fro at its natural frequency. If the case were filled with books, would the natural frequency be lower, greater, or the same as before? I thought that the frequency would be greater because there is more weight to push the suitcase back and forth. Is...

Electromagnetic waves!Conceptual help please! A long steel wire is cut in half is connected to a different terminal of a light bulb. An electromagnetic(EM) plane wave (E(x,y,z,t)=Esin(kx-wt)[y hat direction], B(x,y,z,t)=Bsin(kx-wt)[z hat direction]) moves past the wire. a) Suppose the wire...

Homework Statement QUESTION 1 :A stationary bomb explodes in space breaking into a number of small fragments. At the location of the explosion, the net force do to gravity is 0 Newtons. Which one of the following statements concerning the event is true? a) Kinetic energy is conserved in...

A thick spherical shell of charge Q and uniform volume charge density p is bounded by radii r1 and r2, where r2 > r1. With V = 0 at infinity, find the electric potential V as a function of the distance r from the center of the distribution, considering the regions (a) r > r2, (b) r2 > r > r1...

I need someone to point me towards an instance of a relatively simple QFT problem which illustrates what can be calculated from QFT, how it is calculated, and its physical significance. (Note the qualification "relative". I realize there are likely no simple problems in QFT.) If someone...

Homework Statement A ball is dropped from rest from the top of a building and strikes the ground with a speed vf. From ground level, a second ball is thrown straight upward at the same instant that the first ball is dropped. The initial speed of the second ball is v0 = vf, the same speed...

Need help in understanding the physics behind these physical moments. Can someone please help me how in terms of physics the following things happen? 1) Why does a rocket go up? (what I think is that force emmitted from the flames released from the rocket creates a force that heats the...

Following question is for concept only not an actual problem to solve. Saturated steam is flowing in a 3" diameter pipe under a certain pressure (saturation pressure), temperature and velocity P ,T, v . The 3" diameter pipe expands suddenly to a 24" diameter pipe that is 10 feet long. The...

http://wps.prenhall.com/esm_giancoli_physicsppa_6/0,8713,1115091-,00.html (under practice questions) On questions 16,17, & 18 I'm trying to figure what is the difference between them (Clearly Tc is different, but how does that change the problem?). The question asks The heat engine shown...

Imagine processing the gas clockwise through Cycle 1 and then counterclockwise through Cycle 1. Compare these two processes on the basis of the heat energy transferred to the gas in the entire cycle. Choose the correct comparison symbol. Q_clockwise for Cycle 1 <,=,> Q_counterclockwise for...

Homework Statement A rigid body is rotating about a fixed axis through the origin. The angular velocity is \omega\hat{k} where \omega is positive. What is the unit vector in the direction of the velocity of a point on the body located on the positive y axis? The Attempt at a...

Homework Statement From the beginning of chapter 21 Haliday, Resnick and Walker: `Suppose that you return to your chilly dwelling after snowshoeing through the woods on a cold winter day. Your first thought is to light a stove. But why, exactly, would you do that? Is it because the stove...

A standard mercury thermometer consists of a hollow glass cylinder, the stem, attached to a bulb filled with mercury. As the temperature of the thermometer changes, the mercury expands (or contracts) and the height of the mercury column in the stem changes. Marks are made on the stem to denote...

I have been taking real analysis II this semester and I am starting to get a better grasp over the broad subject of analysis and integration. However, I feel like my understanding is completely problem-oriented. I tried talking to a colleague of mine about real analysis in a conceptual...

Homework Statement to find KE of an orbiting body, do I use 1/2mv^2 or 1/2Gm1m2/r?? Homework Equations The Attempt at a Solution

1. a. Jim and Gina are swinging on adjacent swings of equal length. Jim weighs about twice as much as Gina. Who takes less time to swing back and force. I got this answer, which is that they take the same time since mass doesn't affect the period in simple harmonic motion. However, I don't get...

Homework Statement 3 identical rectangular blocks on frictionless surface have equal magnitudes of force and in the same direction are exerted on them. The CoM is the same for all the blocks and in the center of the rectangle. For block 1, the force is exerted to the left of the CoM, and...

3 forces act on an object. If the object is in translational equilibrium, which of the following must be true? 1. the vector sum of the forces =0 2. the magnitude of the 3 forces must be equal 3. the 3 forces must be parallel would the answer be just 1? I don't think 2 is true because...

This concept would be dependant on having the technology to actually travel at velocities which we can now, only impart to particles Ie: .99c The plan would be to have 3 ships somewhere in space with negligable gravitational effect. 2 of the ships set out in opposite directions...

on a 3d graph i have 3 forces in different places pointing different directions. I am supposed to find the equivalent force-couple system about some point D. but 1 of the forces is aligned with point D and therefore creates no moment about D. how would i do this? Do i just find the moment of...

Are there any good books or website for conceptual physics? I don't seem to have any problem cranking out problems & for the most part I understand fundamental calculus based physics, but then a few conceptual questions will throw me off here & there... so yeah, are there any good supplements...

Homework Statement Person A is seen going down a slide with height "h". A few seconds later the same person A is seen going down a steeper slide with the same height "h" (same height for both slides). Using principles of physics, explain how the new horizontal distance from the edge of the...

Homework Statement A current-carrying ohmic metal wire has a cross-sectional area that gradually becomes smaller. The current has the same value for each section of the wire. How does the resistance per unit length vary? Increase, decrease or constant? Here is what I think: Since the...

A ball is thrown into the air with 100J of kinetic energy. When it returns to its original level after encountering air resistances what is it kinetic energy? I have KE = 0.5m * v^2 I am not sure how to approach this problem as I don't have the mass or the velocity or the height of the...

Homework Statement A certain amount of work Wo is required to accelerate a car from rest to a speed v. How much work is required to accelerate the car from rest to v/2? Homework Equations W = Fd The Attempt at a Solution I know that if we were finding the distance instead of...

I am studying electric flux through both a disk, cube, and sphere. I understand how the flux is calculated in a disk, but I don't understand how the flux through a cube with the point charge outside the cube is equal to zero when the disk is not. Is this because the disk is 2-D? Thank you for...

Homework Statement Define:Static pressure Dynamic Pressure Continuum hypothesis Kinetic Viscosity Kinematic Viscosity 2. The attempt at a solution The real question is : are these answers sufficient? Static Pressure - The pressure exerted by a fluid on an object placed within the...

I have two quick questions about how light bulbs (or any resistor) react in (DC) circuits, as my book's not being very helpful. A) If a light bulb is removed from its socket, ceteris paribus, does current stop flowing through the socket apparatus entirely, and if it precedes all other elements...

Homework Statement GIVEN: mass = .34 kg radius =.5 m If a solid rubber ball attached to the end of a light string is swung at a constant speed in a vertical circle, what is the tension a quarter of the way around the circle (i.e. when the string attached to the...

A football quarterback throws a pass on the run and then keeps running without changing his velocity. Can he throw the pass and then catch it himself? Give your reasoning.

Homework Statement A Ball is thrown straight up. Taking the drag force of air into account, does it take longer for the ball to travel to the top of its motion or for it to fall back down again? Homework Equations None The Attempt at a Solution Do not know where to start...

Hello. I am reading about the wave packet in my physics textbook, and I understood that it describes the probability of a particle having a given position and a momentum in a particular state. However, I just cannot understand where those waves that consist the wave packet come from. I will...

Homework Statement Why is the volume of an ideal gas not important? I'm just asking this for my own studying benefit, it's not technically "homework", although we are studying it. My book says that we can draw the fact that the volume of an ideal gas is not important from the fact that...

Homework Statement Two cars C and D travel in the same direction on a long, straight section of a highway. During a particular time interval \Deltat0, car D is ahead of car C and speeding up while car C is slowing down. During the interval \Deltat0, it is observed that C gains on car D...

1) What is the pattern for how voltage gets distributed in a series circuit with equal resistances? what about with unequal resistances? 2) What about in a parallel circuit for equal resistances? with unequal resistances? In either scenario, is there any relation btwn the size of resistance...