Net Definition and 1000 Threads

Gravitation Force (Solved, thanks) Homework Statement A sphere with mass of 65kg and center at origin. Another sphere with mass 79kg at point (0,3), also centered at origin. A.) What is the magnitude of the net gravitational force due to these objects on a third uniform sphere with mass...

Homework Statement A circular-shaped object of mass 9 kg has an inner radius of 7 cm and an outer radius of 20 cm. Three forces (acting perpendicular to the axis of rotation) of magnitudes 12 N, 27 N, and 16 N act on the object, as shown. The force of magnitude 27 N acts 29 below the...

Homework Statement Block C (m = 4 kg) sits on a frictionless horizontal surface. Block B (of m = 2 kg) sits on top of block C, and is attached to a rope that runs over the massless pulley as shown in the figure. Block A (m = 1 kg) hangs vertically from the rope. With what horizontal force...

In the equation: Wnet=FnetΔX=[m*Δv/Δt]Δx=m*Δv*Δx/Δt I just don't understand how the 3rd part of the equation is changed into the 4rth (Dt going under the Dx). If I can get some help with this, that would be great. The way I think about it is [m*Δv/Δt]Δx = mΔx(Δv/Δt) I have no idea...

how can it be that the net force exerted on the mass m2 be zero?

Homework Statement A car rounds a curve while maintaining a constant speed. Is there a net force on the car as it rounds the curve? Homework Equations none-concept question The Attempt at a Solution yes... centripetal force?

Homework Statement A Gaussian surface in the shape of a cube has edge length 1.14 m. What are (a) the net flux through the surface and (b) the net charge (in C) enclosed by the surface if the electric field in the region is in the positive y direction and has a magnitude that is given by...

Homework Statement A stalled car is being pushed up a hill by 3 people and it is moving at a constant speed the net forcce on the car is a in the opposite of the cars motion b in the same direction as the cars motion-wrong c zero d none of the above Homework Equations noone The...

Homework Statement The Earth is surrounded by an electric field, pointing inward at every point. Assume a magnitude of E = 142N/C near the surface. a) What is the net charge on the Earth? b) How many excess electrons per square meter on the Earth's surface does this correspond to? E...

I made an animation to explain how cats can initiate rotation and turn around during free fall, without violating the conservation of angular momentum: https://www.youtube.com/watch?v=yGusK69XVlk Some footage of real cats: https://www.youtube.com/watch?v=Ua4Gh_4XdwQ...

Homework Statement The coefficient of static friction between a block and a horizontal floor is 0.40, while the coefficient of kinetic friction is 0.15. The mass of the block is 5.0 kg. If a horizontal force is slowly increased until it is barely enough to make the block start moving, what is...

So I was sitting on the train last weekend, reading through my physics book on mechanical work and its relation to kinetic energy. One example would be that a box on a frictionless table being pushed and they would conclude that W = ΔK = ½mΔv2. Looking at this equation got me thinking...

http://www.csmonitor.com/Innovation/Horizons/2011/0923/Net-neutrality-rules-are-coming.-Here-s-why-they-matter" . and http://www.pcmag.com/article2/0,2817,2393442,00.asp" and and If you are alseep under a rock, this is a wake up call... Rhody... :frown:

Homework Statement A ferris wheel at a carnival has a radius of 12 m and turns so that the speed of the riders is 8m/s a) what is the magnitude of the centripetal acceleration of the riders? b) what is the magnitude of the net force required to produce this centripetal acceleration for a...

Homework Statement An advertisement claims that a particular automobile can "stop on a dime". What net force would actually be necessary to stop an automobile of mass 850 kg traveling initially at a speed of 51.0 km/h in a distance equal to the diameter of a dime, which is 1.8 cm? Answer...

What is the net ionic equation of Al(OH)3(s)+3HCl(aq)=AlCl3(aq)+3H20 The answer a got was Cl is the only spectator ion Al3+ +3OH3- +3H3+ = Al3+ +3H2O

Homework Statement An E-field is given as \vec{E}y = b\sqrt{y}\hat{j} V/m. Find the net flux through a cube with vertex at (0, a, 0) and side lengths a. (A picture is attached, but it is essentially the cube that would typically be at the origin, shifted along the y-axis by a units) (You can...

Homework Statement A flea jumps by exerting a force of 1.20 X 10-5 N straight down on the ground. A breeze blowing on the flea parallel to the ground exerts a force of 0.500 X 10-6 N on the flea. Find the direction and magnitude of the acceleration of the flea if its mass is 6.00 X 10-7 kg...

Net force and Newton's laws of motion! Homework Statement A barge is hauled along a straight-line section of canal by two horses harnessed to tow ropes and walking along the tow paths on either side of the canal. Each horse pulls with a force of 490 N at an angle of 19° with the centerline...

Homework Statement Vector V = <x2yz2, xy3z> 0<=x <=a 0 <= y <= b 0<= z <= c Homework Equations \intV \bullet \hat{n}dS In our case, this amounts \int\intV(either x or y component) dot \hat{i} or \hat{j} dA. The Attempt at a Solution Okay, I have tried to break apart the...

Homework Statement The drawing (not to scale) shows one alignment of the sun, earth, and moon. The gravitational force that the sun exerts on the moon is perpendicular to the force that the Earth exerts on the moon. The masses are: mass of sun=1.99 × 1030 kg, mass of earth=5.98 × 1024 kg...

Another http://www.ted.com/talks/mikko_hypponen_fighting_viruses_defending_the_net.html" talk: Mikko is very knowledgeable... Rhody...

Homework Statement Find the net force of 3.4 N i + 3.0 N j and 3.4 N i + -3.0 N j I entered 6.8 N i + 0 N j, It's marking 6.8 as incorrect. Why? Do you not just sum the components??

Homework Statement A basketball player runs down the court, following the path indicated by the vectors A,B, and C in the figure. The magnitudes of these three vectors are 10, 20 and 7 m . Assume the positive x-axis is directed to the right. There is a 45degree angle outside of where A...

Two lightweight metal spheres are suspended near each other from insulated string. One sphere has no net charge, the other has a net charge. The spheres will? Homework Equations None The Attempt at a Solution I know opposite charges attract and similar charges repel, but not sure...

Homework Statement Three point charges are arranged as shown in the figure below. (Take q1 = 5.70 nC, q2 = 4.60 nC, and q3 = -2.79 nC.) (a) Find the magnitude of the electric force on the particle at the origin. (b) Find the direction of the electric force on the particle at the...

Hi, I've got conflicting impressions on the motion of particles in tokamak reactors. Wikipedia says that they generally follow the poloidal field lines due to the Lorentz force, whilst another site claimed that the promising results were due to the random motion of the particles within the...

Homework Statement A rectangular loop wire is placed next to a straight wire, as shown in the figure. There is a current of 3.5 A in both wire. Figure: http://www.flickr.com/photos/65980314@N06/6020832477/ Homework Equations F = ((mu(0)*I1*I2) / (2*pi*r)) * L force in terms of...

If the net electric field inside a conductor is zero, how come electrons flow on applying potential difference across it? What force acts on the electrons? We've been taught that an electric field E sets up, so the force on electrons is eE (e=charge on electron). acceleration a=eE/m (m=mass of...

In a supermarket parking lot, an employee is pushing ten empty shopping carts, lined up in a straight line. The acceleration of the carts is 0.05 m/s^2. The ground is level, and each cart has a mass of 26 kg. a. What is the net force acting on anyone of the carts? b. Assuming friction is...

There are rumors circulating recently on various forums on the internet that a net made of coiled up silver wires increases the efficiency of a gas range when placed on top of the gas burner while fuel is being burned. According to what manufacturers claim, this is done by using the reaction of...

is there any formula of net torque? as we know, net force = momentum / time right? what about net torque?

Homework Statement Given the screen shots I am to calculate net force, Fc and direction, on the red object after 1.00 s Homework Equations The Attempt at a Solution after doing using basic distance formula to calculate r I got a Force for the blue and red at 4.69x10^-3N and...

We know that the built in potential barrier Vb does not allow any net current in a semiconductor. Now when we connect a battery in forward biased with the voltage V the current begins to flow even if V<Vb. Agreed. But my text says that V cannot exceed Vb is this true? for reference...

The general expression for calculating net potential energy in ion is: PE (r) = A r^m + B r^n where A & B are proportionality constants. What exactly are these constants?? Could anyone point me to correct resources?? I'm new at this forum and very interested in learning physics.?

the Earth has a mass of 5.98 x 10^24 kg and the moon has a mass of 7.35 x 10^22 kg. the distance from the centre of the moon to the centre of the Earth is 3.84 x 10^8m. a rocket with a total mass of 1200kg is 3.0 x 10^8 m from the centre of the Earth and directly in between the Earth and the...

Some of the following is more or less Halliday & Resnick, 4th Ed., section 9.8 (not the whole section and I added a lot): Assume motion in a stright line. Therefore, for position, velocity, acceleratiom, force, momentum, etc., d/dt|vector|=|d/dt(vector)|. This is not true in general for...

An interesting electrostatics puzzle! This is a simplification of a real problem I've been hurting my brain on. Luckily the simplification is a fun challenge in its own right. Homework Statement There is a 3D rectangular solid object in space. Each face of the solid is a perfect...

Homework Statement Motorcycle in a vertical loop. Traveling at 50 m/s. Assume g=10 m/s^2 Find the maximum height of the loop. h=? Homework Equations F(net) = F(cent) + F(grav) F(cent) = mv^2/r F(grav) = mg (change) KE = (change) PE KE = 1/2 mv^2 PE = mgh The Attempt at a Solution F(net)...

Homework Statement In a region of two-dimensional space, there are three fixed charges: +1 mC at (0, 0), −2 mC at (15 mm, -2 mm), and +3 mC at (-5 mm, 15 mm). What is the net force on the −2-mC charge? ? magnitude ? direction ° counter-clockwise from...

If a nuke units has a DNC of 1000 MWe, is this capacity per sec, hour, day, or year? I'm "assuming" this capacity is per hour but then again a Watt is a unit of seconds. In other words, If a nuke unit has declared net capacity (DNC) of 1000 MWe, how long would the unit have to run at...

Homework Statement "A 6.0 kg box is held at rest by two ropes that form 30-degree angles with the vertical. An external force F acts vertically downward on the box. The force exerted by each of the two ropes is denoted by T. . . . The magnitude of force F is 410 N. The magnitude of force T...

Homework Statement A resting 164 g hockey puck is hit with a force of 15.3N. The frictional force slowing the puck down is 0.75N. a) Find the net forces acting on the puck. Remember to consider both horizontal and vertical forces b) If the puck leaves the stick with a velocity of 45m/s...

Homework Statement Show that the net work done by the otto engine per cycle is Cv(Tc - Tb)(1 - Ta/Tb) PV diagram: [PLAIN]http://www.antonine-education.co.uk/physics_a2/options/module_7/topic_4/Otto_indic.gif Homework Equations Work done by a kmole of gas expanding irreversibly and...

Homework Statement Two ropes are attached to a log that is floating in the water. A force of 80.0 N is applied to one rope and a force of 60.0 N is applied to the other rope, which is lying at an angle of 40° from the first rope. What is the net force on the log? We know that the angle...

Homework Statement A person with a skin temperature of 33 C and an emissivity of .9 is in a room at 24 C. What is the net power transfer by radiation. Let the area of the body be 1.8 m2. Homework Equations I=\frac{P}{A} \DeltaIrad=\epsilon\sigmaT4 (Stefan-Boltzman Law) The Attempt...

Three blocks are bring accelerated upwards at 3.2m/s2, by a force applied to the bottom block as shown in the figure. The mass of the bottom block is 12kg, the mass of the middle block is 24 kg, and the top block is 36 kg. What is the net force on the top block? a.44.8 N b.67.2 N c.115.2 N...

Homework Statement A closed surface with dimensions a = b = 0.294 m and c = 0.3528 m is located as in the figure. The electric field throughout the region is nonuniform and given by \vec{}E = (\alpha+\beta x2)ˆı where x is in meters, \alpha = 2 N/C, and \beta = 4 N/(Cm2). See figure...

Homework Statement Three charges of equal magnitude q reside at the corners of an equilateral triangle of side length a. The topmost charge is positive while the charges at the bottom left and bottom right of the triangle are negative. If point P is midway between the negative charges, at...

Just need some clarification as to whether or not I'm doing this right. 1 drop HCl and several drops KMnO4 added to 2mL NaHSO3. HSO3- → HSO4- + 2e- MnO42- + 4e- → MnO22- 2HSO3-(aq) + MnO42-(aq) → 2HSO4-(aq) + MnO22-(aq) A few questions: -Since NaHSO3 is not an acid, the hydrogen atom...