Net Definition and 1000 Threads

Homework Statement During a tennis match, a player serves the ball at 25.3 m/s, with the center of the ball leaving the racquet horizontally 2.50 m above the court surface. The net is 12.0 m away and 0.900 m high. When the ball reaches the net, (a) what is the distance between the center of...

Homework Statement In a cathode ray tube, electrons are accelerated from rest by a constant electric force of magnitude 6.4E-17 N during the first 2.0cm of the tubes length; then they move at essentially constant velocity another 45cm before hitting the screen. A) Find the speed of the...

Homework Statement The box-like Gaussian surface of the figure below encloses a net charge of +57.0ε0 C and lies in an electric field given by = [(10.3 + 2.4x)·i - 3.1·j + bz·k ] N/C, with x and z in meters and b a constant. The bottom face is in the xz plane; the top face is in the...

[SOLVED] Two point charges, Zero Net Force Homework Statement Two point charges of charge 7.40 μC and -1.80 μC are placed along the x-axis at x = 0.000 m and x = 0.300 m respectively. Where must a third charge, q, be placed along the x-axis so that it does not experience any net force because...

Homework Statement Make the following into a web address; it wouldn't let me post one. img161.imageshack.us/img161/3728/physicspv5.pngimg161.imageshack.us/img161/3728/physicspv5.b3825b8665.jpg[/url] What is the net torque on this object? Homework Equations torque=(radius)(force)(sin(...

I'm trying to write a Library entry on Reaction Force, and I've discovered I can't answer this very simple question. :redface: Two equal blocks are on a horizontal table, with a gap between them. A straight rod is placed above the gap, but not symmetrically, resting on both blocks, with an...

The Earth is effectively an insulator in space, and the sun continuously beats on the Earth with protons, electrons and other particles. Does the planet Earth and all other planets have a net charge, and if so, how can we measure the polarity and extent of that charge? Turning to the Sun...

Homework Statement What is the net change in entropy of the system from the time of mixing until the moment the ice completely melts? The heat of fusion of ice is . Note that since the amount of ice is relatively small, the temperature of the water remains nearly constant throughout the...

Hello everyone, Could someone please help me with this problem? Homework Statement A 145kg object and a 445kg object are separated by .420m. a. Find the net gravitational force exerted by these objects on a 41.0kg object placed midway between them. b. At what position can the 41.0kg...

Homework Statement The speed of a particle doubles and then doubles again because a net external force acts on it. Does the net force do more work during the first or the second doubling? Justify your answer. Homework Equations I'm not sure, but i think E = 1/2 mv(squared) The...

A sailboat is moving at a constant velocity. Is work being done by a net external force acting on the boat? Explain. The speed of a particle doubles and then doubles again because a net external force acts on it. Does the net force do more work during the first or the second doubling...

Wnc = delta (kinetic energy) + delta(potential energy) (Work done by nonconservative forces) = (change in kinetic energy) + (change in potential energy) Now, my professor gave us this formula instead of the one above: W - H = (change in kinetic energy) + (change in potential energy)...

I have a problem in trying to express a net force equation for a falling elastic object when collision ensues. For instance, you drop a spring with a spring coefficient k. the spring compresses a distance x after a time t for a maximum time of tf and distance xf. the spring has a weight W...

Homework Statement The Bruce Nuclear Development is a CANDU style reactor. This means that it has a "vaccum building" to "suck" (the contents of a malfunction reactor to a safer place. Refer to the engineering "specs" for the needed information to calculate the net force of the atmposhere...

A plane is diving toward the ground and then climbs back upwards as shown below. A lift force acts perpendicular to the plane's displacement, s = 1.7 x 10^{3} m, which should be taken to be the same for each case. The engines of the plane exert a thrust as shown which has the same magnitude...

[SOLVED] Net Force of object changing velocity Hi, I'm studying for a test, so there might be a few of these in the next hour or so. Homework Statement A supertanker of mass 1.0 X 10^{8} kg travels 3.5km, reaching a speed of 4.1km/h from rest. What was the magnitude of the unbalanced force...

[SOLVED] I really need help I understand the very simple questions and all, but when the book throws all these extra things at me, I get so lost. You might've remembered my earlier post (my first one), so I'm back with a bit more. If it takes a human cannonball 1.5s to exit a 1.6m long...

A constant nonzero net torque is exerted on an object. Which of the following can not be constant? Choose all that apply. -angular position -angular velocity -angular acceleration -location of center of mass -moment of inertia -kinetic energy My guess is...

I'm having trouble understanding the CNIE process. It would be very much appreciated if someone could show me how to solve a sample problem.

Harvard has now put up streaming videos of Sidney Coleman’s 1975-1976 Quantum Field Theory lectures. Bryan Chen has also transcribed the first eleven lectures to TeX format!. http://www.physics.harvard.edu/about/Phys253.html http://www.physics.upenn.edu/~chb/ So, good for anybody that's...

Homework Statement will a body necessarily remain at rest if the net force acting on it is zero?give a reason for ur answer...and I've just passed my ninth grade so if u cud please it to me explain at that level...:smile: Homework Equations The Attempt at a Solution

A ballerian spins initially at 1.5rev/s when arms are extended. She then draws in her arms to her body and her moment of intertia is .88kg m^2 and her angular speed increases to 4.0rev/s. Determine the network she did to increase her angular speed? To find moment of inertia was pretty simple...

A ballerian spins initially at 1.5rev/s when arms are extended. She then draws in her arms to her body and her moment of intertia is .88kg m^2 and her angular speed increases to 4.0rev/s. Determine the network she did to increase her angular speed? So i first needed to solve for the initial...

A toy car of mass 50g travels down a smooth incline at 30 degrees to the horizontal. Friction can be ignored. Also Gravity is assumed to be 10ms Calculate the net force on the car as it rolls down the slope: For this I use M x G sin 30 so .05 x 10 sin 30 and got .25N - Hopefully...

The figure below shows plots of the current i through a certain cross section of a wire over four different time periods. Rank the periods according to the net charge that passes through the cross section during the period, greatest first. (Use only the symbols > or =, for example a>b=c>d.)...

Forces/Friction I'm new, so I'd like to say thanks in advance for helping me. The site wants all answers to the 4th decimal place. Idk how stuff normally works around here, but a small explanation with the answer would help me understand this stuff better. 1. Three forces act on a particle...

Can anyone help me through this net ionic equation problem? Pb(ClO4)2 (aq) +NaI (aq) -> PbI2 (s) + NaClO4 (aq)

Homework Statement Two 10 kg masses are placed on an x-y coordinate plane measured in meters. the first mass is at position (0,0) and the second at (2,0). that's the first part of the problem the second part is: if an additional 5 kg mass is placed at the point K, calculate the gravitational...

Calculate the net torque about point for the two forces applied as in the figure below The rod and both forces are in the plane of the page. torque= ? Nm http://session.masteringphysics.com/problemAsset/1026433/5/yg.10.42.jpg i know that F2 = 0 since its pointing through point 0...

Let's say for the: First 10 milliseconds: Current is 1 milliamp. The squared magnetic field resulting we will call "default". 1 millisecond following, last millisecond: Current is -10 milliamps. The squared magnetic field is -100 * "default". The time average square of the magnetic...

Homework Statement g=10m/s^2 A fully loaded Saturn rocket has a mass of 2.92x10^6kg. Its engines have a thrust of 3.34x10^7N. a) How much does the rocket weigh. answer 2.92x10^7 N b) What is the net force on the rocket when it blasts off? answer 4.2x10^6N c) What is the...

Hi I'm wondering if you could help me with a problem I am having. I am currently mid process of designing a device used to measure tension in a tennis net, and I am stuck at trying to calculate the deflection in the net cord on ball impact. I have calculated that the ball will impact the...

1. A man is lazily floating on an air mattress in a swimming pool. If the weight of the man and air mattress together is 740 N, what is the upward force of the water acting on the system of man and mattress? 2. A truck driving on a level highway is acted upon by the following forces: a...

If I were to take an enclosed object, like a rock, container, etc... and put it within an electric field any distance away from the source charge (so long as the source charge isn't inside the object)...would the net electric flux always be zero?

Homework Statement The following amounts of substances are added to a 7.25 L reaction vessel at 773K: (.103 mol CO) , (.205 mol H2), ( 2.1 mol CH4), ( 3.15 mol H20). In what direction will a net reaction occur to react equilibrium. CO(g) + 3H2(g) --------> CH4(g) + H20 (g)...

Homework Statement I really can't see where I am going wrong here. I would latex out my work, but it would take way too long, so I have scanned it in. It should be easy enough to read though. Its NUMBER 7, fig 21-22 Also the blurr says '100 nC' The Attempt at a Solution

Hello, are there any websites of solved exercises and problems in electrical engineering,especially ohm's law,kirchoff's laws and nodal analysis? Thanks

Homework Statement Particles 2 and 4, of charge -e, are fixed in place on the y-axis at y2=-10.00 cm and y4=5.00cm. Particles 1 and 3, of charge -e, can be moved along the x axis. Particle 5 of charge +e is fixed at the origin. Initially particle 1 is at x1= -10.0cm and particle 3 is at x3=...

Homework Statement A metal sphere has a charge of +8.0 µC. What is the net charge after 9.00 *10^13 electrons have been placed on it? Homework Equations q=Ne where q is the charge, N is the number of electrons, and e is given as 1.6*10^-19 The Attempt at a Solution Well...

I am having some trouble getting started with this problem. Do I want to use kq/r^2 at all or should I be doing something else? The problem is: Two point charges, Q1=-6.7 microCoulombs and Q2= 1.3 microcoulombs, are located between two oppositely charged plates. (The positively charged...

[SOLVED] Help needed with Gauss's Law and Net Flux A cube of side l-55cm is placed in a uniform field E= 7.30 X10^3 N/C with edges parallel to the field lines. a. what is the net flux through the cube? b. what is the flux through each of its six faces? Face 1 perpendicular to E (field...

Homework Statement A 65 kilogram tightrope walker falls vertically downward with a velocity of 9.9m/s. She falls into a net which stretches 1.5m vertically as it breaks her fall. What is the average net force on the walker as her fall is being broken, and what is the G force that she...

Homework Statement There is an uneven arrangement of electrons and protons on a circular arc of radius r = 2 cm with an electron (E1) at 0 degrees, a proton (E2) at 30 degrees, an electron (E3) at 80 degrees, an electron (E4) at 130 degrees, and a proton (E5) at 160 degrees. What are the...

[SOLVED] Net Force Question with no velocity or time given. Homework Statement A ball of mass 0.6 kg flies through the air at low speed, so that air resistance is negligible. What is the net force acting on the ball while it is in motion? Homework Equations Fnet = m(change in...

Homework Statement An airplane is flying at an elevation of 12500 m. The window on an airplane is a square of length 0.115 m on each side. What is the net force on the window? Homework Equations P = Po + pgh p = 1.26 kg/m^3 Pair = 101.3 kPa The Attempt at a Solution I thought...

[SOLVED] Ratio of net gravitational pull on moon A new moon is almost exactly in line between the Earth and the sun. A full moon is on the opposite side of the Earth from the sun. What is the ratio of the net gravitational force on the moon when it is new to when it is full? I tried...

Net Electric Charge...Please help! Homework Statement What is the net electric force on charge A? (s=1.41 cm, q1=1.1 nC, q2=0.72 nC, q3=5.21 nC. Force is positive if it points to +x direction.) Homework Equations F = (K * Q * Q) / r^2 The Attempt at a Solution F2on1 = (K * Q1 * Q2) / r^2...

Homework Statement A metal sphere has a charge of +7.0 µC. What is the net charge after 8.00 10^13 electrons have been placed on it? in µC Homework Equations The Attempt at a Solution I believe that the charge of an electron is: -1.6 x 10^-19 C and there are 8 electrons...

[SOLVED] Law of gravitation In Figure 13-34, a square of edge length 15.0 cm is formed by four spheres of masses m1 = 5.00 g, m2 = 4.00 g, m3 = 1.50 g, and m4 = 5.00 g. In unit-vector notation, what is the net gravitational force from them on a central sphere with mass m5 = 2.10 g? I know...

Two blocks of masses M_1 and M_2 passes through a pulley (See the Fig. attached.). Assuming the friction between block and the incline is zero, and neglecting the mass of string find the net torque about the center of mass of the pulley. I solved this problem with two different ways. The...