What is Net force: Definition and 504 Discussions

Net force is the vector sum of forces acting on a particle or body. The net force is a single force that replaces the effect of the original forces on the particle's motion. It gives the particle the same acceleration as all those actual forces together as described by Newton's second law of motion.
In physics, it is possible to determine the torque associated with the point of application of a net force so that it maintains the movement of jets of the object under the original system of forces. Its associated torque, the net force, becomes the resultant force and has the same effect on the rotational motion of the object as all actual forces taken together. It is possible for a system of forces to define a torque-free resultant force. In this case, the net force, when applied at the proper line of action, has the same effect on the body as all of the forces at their points of application. It is not always possible to find a torque-free resultant force.

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  1. A

    Net force and acceleration as a result of a parachute

    Homework Statement Homework Equations F= maThe Attempt at a Solution For 8, I think the parachute causes Al and Betty to stop accelerating, so they both have the same net force. (Answer A) F= ma F=m*0=0 F=3m*0=0 For 9, I feel like Al should experience more air resistance than Betty to make...
  2. D

    Position of a charge (out of 3) with a net force of 0

    Homework Statement Point charges ##q_1=50 \mu C## and ##q_1=-25 \mu C## are placed 1.0 m apart. Where must a third charge ##q_3=20 \mu C## be placed so that the net force on it is zero? Homework Equations $$\vec F=\frac{1}{4\pi {\varepsilon}_0}\frac{|q_1q_2|}{r^2}\hat r$$ The Attempt at a...
  3. N

    Net force from a varying speed non-uniform rotating wheel?

    If we have a circle rotating then a force v^2/r is produced but no net directional force exists as it cancels. But if the wheel was not uniform in mass ie not rotating around its centre of mass AND the speed changes over time as a function of the "wheel"'s rotation angle could a net force be...
  4. S

    What is the torque on an electric dipole in an electric field?

    Homework Statement A charge Q is fixed at the centre of a train track, radius R. An electric dipole with charges Q, -Q, separated by distance d. Show that the net force on the dipole is given by F = Q2d/(4πε0R3) b) What direction is this force? c) What is the torque on the dipole? Homework...
  5. A

    Finding net gravitational attractions in a triangle

    1. The problem is attached in a picture. I've done it five times and keep getting it wrong. The correct answer is also displayed in the picture. Thank you for any help. 2. Fg=Gm_1m_2/r^2 3. I calculated Fg between AB and BC (they are equal). So Fg=(6.67*10^-11)(4)(4)/(.10)^2=1.067*10^-10...
  6. Arshavsky

    Net force on a Halbach Array in a uniform magnetic field

    I have been unable to determine whether a Halbach Array of permanent magnets would experience a net force in a uniform magnetic field.
  7. C

    B Calculating Net Force on Two Books: Explanation and Example

    This is an example given in my textbook: "On a frictionless horizontal surface, you push with a force ##\vec{F}## on a book of mass ##m_1## that in turn pushes on a book with a mass ##m_2##. What force does the second book exert on the first?" First they calculate the acceleration of book 2...
  8. Angelnomahou

    Newton's Second Law Homework: Forces, Accelerations, Angles

    Homework Statement The two forces F⃗ 1 and F⃗ 2 shown in (Figure 1) act on a 29.0-kg object on a frictionless tabletop. Suppose that F1 = 10.8 N , and F2 = 19 N . A. Determine the magnitude of the net force on the object for the diagram (a) in the figure. B.Determine the angle between the...
  9. T

    Net Force acting on block on incline

    Homework Statement A 6.50 kg block is placed on an inclined surface. The coefficients of static and kinetic friction between the block and the surface are 0.685 and 0.485, respectively. The incline makes an angle of 18.8° relative to horizontal. The block is at rest and remains at rest. What is...
  10. jlmccart03

    Finding magnitude and direction of net force on a dipole.

    Homework Statement A dipole with charges ±q and separation 2a is located a distance x from a point charge +Q, oriented as shown in the figure. Part A: Find an expression for the magnitude of the net force on the dipole in the limit x≫a. Part B: What is the direction of the net force...
  11. Schaus

    Electric fields - Finding Net force acting on Q2

    Homework Statement What is the Net force (include direction) acting on charge Q2 due to Q1 and q? (ans: Fnet = 174N right) Homework Equations F=kQ1Q2/r2 E=F/QThe Attempt at a Solution I've figured out a) and b). It's just c) that's giving me trouble. I tried using the first equation - (9.0 x...
  12. W

    Understanding Net Force and Net Moment in Statics

    Homework Statement Homework Equations I can see how the net force is not the same but I'm not getting the net moment. The Attempt at a Solution 12mm x 10N = 120N-mm. How do these two FBDs not have the same net moments. Thanks for any help!
  13. L

    To help reduce the severity of accidents [Average net force]

    Homework Statement To help reduce the severity of accidents, an engineering company designs large plastic barrels filled with antifreeze that can be placed in front of bridge supports. In a simple test, a 1200 kg car moving at 20 m/s [W] crashes into several barrels. The car slows down to 8.0...
  14. Dusty912

    Find an expression for the net force of water on a dam

    Homework Statement Find the net force of water on the dam The dam has a width of w and the water is at a depth of d. So my question is, would you have to integrate ρgwd with respect to d? because the pressure is constantly changing every value of d. Homework Equations ρgwd ρ is the density of...
  15. B

    Finding magnitude of tension that causes object to slip

    Homework Statement A rope attached to a 19.0 kg wood sled pulls the sled up a 19.0° snow-covered hill. A 14.0 kg wood box rides on top of the sled. EDIT: the actual question to be answered, oops. What's the magnitude of the tension that will cause the box to slide? Mass of box (mb) = 14.0kg...
  16. O

    B Net force on 'ground' with object on top of it....?

    A stationary object resting upon the ground experiences two forces, the weight force as well as the normal reaction force of the ground. These forces sum to zero. The ground however experiences the weight force acting downwards upon it. What other force acts upon the ground to prevent it from...
  17. roguekiller93

    Calculate the net force acting on the object

    http://[PLAIN] [PLAIN][PLAIN]http://[PLAIN] 1. Homework Statement Calculate the net force acting on each object indicated in the following diagrams. (diagrams attached) I am working on "B" Homework Equations Sine Law: sin a/a = sin b/b = sin c/ c Cosine Law: c^2 = a^2 + b^2 -2ab*cos(c)...
  18. R

    How is there no net force in this situation

    Homework Statement [/B] A man pushes on a piano with mass 190 kg ; it slides at constant velocity down a ramp that is inclined at 17.0 ∘ above the horizontal floor. Neglect any friction acting on the piano. A. Calculate the magnitude of the force applied by the man if he pushes parallel to the...
  19. roguekiller93

    Calculate the net force acting on the object in the diagram

    Homework Statement Calculate the net force in Diagram B. Homework Equations Sine Law: sin a/a = sin b/b = sin c/ c Cosine Law: c^2 = a^2 + b^2 -2ab*cos(c) The Attempt at a Solution c^2 = (2N)^2 + (17)^2 -2(2)(17)*cos(45) = 16 N sin b/ 17N = sin45/16N = 49 degrees Fnet = 16 N (W 49 degrees N)...
  20. R

    Net force in a Non-Uniform magnetic field

    When there is a magnetic dipole placed in an external non uniform magnetic field, will it experience a net force?
  21. E

    Lifting a 3m Beam: Calculating Force, Friction, & Net Force

    [mentor note: moved here from another forum, hence no homework template.] A construction worker attempts to lift a uniform beam off the floor and raise it to a vertical position. The beam is 3.00 m long and weighs 372 N. At a certain instant, the worker holds the beam momentarily at rest with...
  22. alxkrgr

    Where to place a third charge so it experiences no force

    Homework Statement A point charge of 5.6 microcoulombs is placed at the origin (x=0) of a coordinate system, and another charge of -1.9 microcouloumbs is placed on the x-axis at .29m. Where on the axis can a third charge be placed so that it experiences no charge? q1= 5.6 E-6 q2= -1.9 E-6 d=...
  23. Zack K

    Acceleration of an object given forces

    Homework Statement An 85 kg tobbogan that was originally accelerating at 3.0 m/s2 on frictionless snow hits a bare patch of concrete that exerts a force of friction on the sled of 180 N, what will the new acceleration be? Homework Equations F=maThe Attempt at a Solution Ok so this was...
  24. Kaneki123

    How a net force acts on 'Earth'?

    Hi, Newton's 2nd Law states that when a net force acts on a body, it causes acceleration in the body...This is well for forces acting on bodies in space...But what about on Earth??...On Earth when you apply force to an object, the air around it pushes back with same force!, So where is the...
  25. B

    Net force =0 or Net force =GM^2/4R^2....?

    Two stars of equal mass M move with constant speed V in a circular orbital of radius R about their common center of mass .What is the net force on each star?the answer to this question was net force=GM^2/4R^2 .I want to ask that why net force not equal to zero although it is in translational...
  26. steroidjunkie

    Net force on a charge ##Q_3##

    Homework Statement Two point charges ##Q_1 = 9 \mu##C and ##Q_2 = -16 \mu##C are fixed in space on a distance r=7cm. At what distane ##x_1## from the first charge, and ##x_2## from the second charge, should we place the third charge ##Q_3## so that net force on ##Q_3## is zero? make a sketch...
  27. defaultusername

    Tension and Angle Analysis for Traction in a Broken Leg

    Homework Statement An accident victim with a broken leg is being placed in traction. The patient wears a special boot with a pulley attached to the sole. The foot and boot together have a mass of m = 4.0 kg, and the doctor has decided to hang a 6.0 kg mass from the rope. The boot is held...
  28. K

    Calculating Net Force: A Step-by-Step Guide

    Homework Statement Calculate the net force on A.[/B] Homework Equations F=k . (q1 q2)/r^2 , k=9 x 10^9 Nm^2/C^2[/B]The Attempt at a Solution (9*10^9 Nm^2/C^2)(1,4 x 10^-6C)(7,2 x 10^-6C) / 1,7mm^2 = 0,0313. Could someone tell me what I am missing even if what i did is even correct. Thanks[/B]
  29. Evangeline101

    Net force of object indicated in following diagram

    Homework Statement Calculate the net force acting on the object indicated in the following diagrams. Show your work. 1) 2) Homework Equations [/B] The Attempt at a Solution 1) 8.0 N (north) + 10.0 N (south) - 8.0 N (south) + 10.0 N (south) = 2.0 N (south) c= [ (2.0 N) 2 +...
  30. Evangeline101

    Calculating the net force acting on object in diagram

    Homework Statement Calculate the net force acting on each object in the following diagrams. Show your work. Homework Equations [/B] The Attempt at a Solution c2= a2 + b2 - 2abcosC c = (a2 + b2 - 2abcosC) 1/2 c = [ (32.0 N)2 + (38.0 N)2 - 2 (32.0 N) x (38.0 N) cos 55° ] 1/2 c = 32.8 N...
  31. Jai Singh

    The net force on the charge placed at origin

    Ques: If infinite number of charges placed along x-axis .At x=1, 1μC , x=2, 2μC, x=3, 3μC so on. Find the net force on charge 1μC placed at origin.Formula used (1/4πε)*q1*q2/r² Solved from this formula but stuck in a series
  32. J

    Need Conceptual Framework for Reaction vs. Net Force

    I find the common physics problem of accelerating boxes that are touching very confusing. (To be clear, boxes are on surface, force comes from one side and all boxes accelerate. Questions typically ask about magnitude of force between particular boxes). Once the boxes are accelerating, why is...
  33. T

    Question of electricity net force

    Homework Statement Three point charges are located on the positive x-axis of a coordinate system. Charge q1 = 1.0 nC is 2.0 cm from the origin, charge q2 = -3.5 nC is 4.0 cm from the origin and charge q3 = 6.0 nC located at the origin. What is the net force ((a)magnitude and (b) direction) on...
  34. Marleycake

    Net Force and Direction of motion

    Homework Statement Is the direction of net force always in the direction of motion? The Attempt at a Solution I would say no because the net force could be equal/balanced for example if two kids were pulling on a stick 2 N left <---- . ----->2 N right the Total Net Force would be 4 N with...
  35. alexandria

    How do I use the tip-to-tail method to add vectors and calculate net force?

    Homework Statement Homework Equations The Attempt at a Solution 32° + 24° = 56° I used the tip-to-tail method to add vectors c = ([12 N]^2 + [15 N]^2 - 2 [12 N] x [15 N] cos124°)1/2 c = 23.9 N SinA/12 N = Sin124° / 23.9 N (i don't know how to solve this part) can someone please...
  36. alexandria

    Calculating Net Force Using Vector Addition

    Homework Statement Homework Equations The Attempt at a Solution 8.0 N (north) + 10.0 N (south) = 2.0 N (south) i used the tip-to-tail method to add the vectors c = ([2.0 N]^2 + [17.0 N]^2 - 2 (2.0 N) (17.0 N) cos45°)1/2 c = 15.6 N SinA/17.0 N = Sin45°/15.6 N A = 40° Net force = 15.6 N...
  37. alexandria

    Forces - calculating the net force

    Homework Statement Homework Equations The Attempt at a Solution c = ([32.0 N ]^2 + [38.0 N]^2 - 2 (32.0 N)(38.0 N) cos70° ) 1/2 c = 40.5 N (is this correct?) SinA / 38.0 N = Sin110° /40.5 N (im unsure how to solve this part) A = ?? net force = 40.5 N (East ? North) I am very confused...
  38. Haley Heldt

    How Do You Calculate Net Force on a Diver?

    Homework Statement An 82 kg man drops from rest on a diving board 3 m above the surface of the water and comes to rest .55 s after reaching the water. What is the net force on the diver as he is brought to rest Homework Equations FDt = mv F = mg v^2 = vi^2 = 2aDx Dx = 3m Dt...
  39. B

    How Does Friction Impact Bobsled Acceleration?

    Homework Statement In the men's four-man bobsled event in the winter olympics, the maximum mas of a bobsled with pilot, two riders, and a brakeman is 630 kg. During a practice run, the rear rider and the brakeman exert average forces of 1220N and 1200N [forward] respectively to accelerate a...
  40. B

    Net Force on 5.32 x 10^4 kg Airplane: Solve the Mystery

    Homework Statement An airplane with a mass of 5.32 x 10^4 Kg accelerates down the runway at 1.76 m/s^2 [forward]. Calculate the net force acting on the airplane. Homework Equations Fnet=ma The Attempt at a Solution I did this by multiplying the two given values, but my answer was 93632N...
  41. T

    What direction is the net force acting on a car going around a circular track?

    Homework Statement A car is going around a circular track at constant velocity. What direction is the net force acting on the car pointing to? Homework Equations Fnet = ma[/B] Fnet = m(v^2/r) --> don't really know if this will help me understand it, but if this will help me understand what's...
  42. J

    Forces on an Object Sliding at 8.0 m/s

    Homework Statement An object slides across a table at a constant 8.0 m/s to the right. The net force is... A) zero B) equal to the weight C) equal to the mass times the velocity D equal to the friction force Homework Equations N/A 3. The Attempt at a Solution Bu narrowing it down i don't...
  43. O

    Torque and Net Force Calculations

    Homework Statement The bar, of length AB=2m, with a mass of 6.00 kg. There are two weights, let's call them m1 and m2, hanging off the bar. m1 is 4.4kg, at 0.66m from point A. m2 is 2.0 kg, at 1.84m. The bar is suspended by two spring scales defined as F1 and F2 (assuming negligible mass)...
  44. Mr.Y

    Relation between Tension and net force

    I am having a lot of difficulty understanding this concept. Suppose you have two objects A,B of mass A',B' connected by a massless rope. Let K Newtons be the force applied on object A .What is now the tension along the rope ? -My reasoning: K Newtons is the force applied to the combination...
  45. Alexstrasza

    Question about net force and acceleration

    Homework Statement Picture related [/B] 1. There is a system of two blocks tied to each other. There is a force F on the small block causing the system to move at a certain acceleration. Find the acceleration. 2. (This is the one I'm not sure about) Instead of force F, we add a pulley with a...
  46. REVIANNA

    Power associated with net force

    Homework Statement How to prove : [/B] ##P*F_net=((dK)/(dt))## i.e. power associated with the net force is the rate of change of kinetic energy. The Attempt at a Solution [/B] if I use the definition of power ans then that of work I get (m*a*ΔS )*(F_net) further using F_net=ma LHS=...
  47. R

    Net force acting on a piston shaft of an actuator

    Homework Statement A cylindrical piston shaft weighs 250 g and is held vertically inside an actuator (We can assume actuator is a box with hollow cylindrical space to fit the piston shaft). Compressed air at 100 psi is supplied at the bottom of the actuator and is acting on the piston upwards...
  48. B

    Accelerometer on a rotating wheel- Net force calculation

    Homework Statement I have two analog MEMS accelerometers ADXL337, ADXL377. The ADXL337 can measure acceleration upto +/- 3g (where g = gravitational acceleration) and ADXL377 can measure upto acceleration of +/- 200g. More than this much amount of acceleration, would create noise and random...
  49. B

    Finding net force or acceleration given 2 masses

    Homework Statement Imagine you put 10 weights of 100grams on wheels. You attach this "car" to a pulley that hangs over a ledge. You take 1 weight of 100grams off the "car" attach it to the hanging edge of the pulley. The car propels forward what was the acceleration of car and/or net force...
  50. F

    Finding direction of net force and direction of travel

    Homework Statement A 0.35 kg particle moves in an xy plane according to x(t) = - 11 + 1 t - 6 t3 and y(t) = 19 + 3 t - 8 t2, with x and y in meters and t in seconds. At t = 0.7 s, what are (a) the magnitude and (b) the angle (within (-180°, 180°] interval relative to the positive direction of...
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