What is force vector: Definition and 49 Discussions

In physics, a force is an influence that causes the motion of an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. It can be a push or a pull, always with magnitude and direction, making it a vector quantity. It is measured in the SI unit of newton (N) and represented by the symbol F (formerly P).
The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time. If the mass of the object is constant, this law implies that the acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, and is inversely proportional to the mass of the object.
Concepts related to force include: thrust, which increases the velocity of an object; drag, which decreases the velocity of an object; and torque, which produces changes in rotational speed of an object. In an extended body, each part usually applies forces on the adjacent parts; the distribution of such forces through the body is the internal mechanical stress. Such internal mechanical stresses cause no acceleration of that body as the forces balance one another. Pressure, the distribution of many small forces applied over an area of a body, is a simple type of stress that if unbalanced can cause the body to accelerate. Stress usually causes deformation of solid materials, or flow in fluids.

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  1. E

    Vector is a function of its position or not?

    At first I thought that this force vector ## \vec F = 3 \hat x + 2 \hat y ## is a function of ## x ## and ## y ##, which is to say that its magnitude and direction vary with the x and y positions, but this is not so, right? It's just a force with a constant magnitude and direction. And I can...
  2. X

    Y-component of the force vector in turning flight

    Hello, I have a question: Why is the y-component of the force at turning flight equal to the weight force? Here, Fs is equal to Fg. But why? I tried to explain it myself but I didn't get it
  3. JD_PM

    Arguing about the magnetic force vector

    I am writing about the nature of force in classical mechanics and what does really imply, in terms of change in motion. I am using as an example a circuit, on which we exert a force. I am trying to justify the following scheme (concretely, ##f_{mag}##): The thing is that I am wondering how...
  4. T

    Why is force vector F but acceleration vector a not A?

    Is there some rule or standard that determines whether we define a vector with upper or lower case? I have not been told of any particular rule but it seems with velocity and acceleration they are lower case but force has always been upper case from what I've been reading so far. Is there a...
  5. starstruck_

    Calculating total Coulomb force vector ?

    Homework Statement Consider a configuration consisting one +q charge ( upper right) and three −q charges, arranged in a square. Side lengths = d. Calculate the total F force vector acting on charge +q.Homework Equations Vector form of culomb’s force F=( kq1q2/r^2) rhat (rhat for unit...
  6. Frankenstein19

    Help finding the angle between the force vector and line AO

    Homework Statement Find: The angle between the force vector and the line AO, and the magnitude of the projection of the force along the line AO Homework Equations cos(theta)=(A*B)/(|A|*|B|) The Attempt at a Solution I thought that since I'm given the force F in cartesian form, that I would...
  7. Erenjaeger

    Finding direction of force vector

    Homework Statement The magnitude of a force vector is 80.6 Newtons (N). The x component of this vector is directed along the +x axis and has a magnitude of 78.0 N. The y component points along the +y axis. (a) Find the angle between and the +x axis. (b) Find the component of along the +y...
  8. I

    Pulley Force Vector: Check Friction on 10kg Weight

    I'd like to ask the question as above, I think it successfully acted as a lever and redirected the force vector perpendicular to the arm of the machine, but it does've > friction, reducing the force acting on the 10kg Weight, could anyone that knows pls help check for me?*Edit, ... I think it...
  9. S

    Finding position coordinates from given force vector

    1. A particle of mass m initially at rest at the origin is acted upon by a force (vector) F = xi+yj+zk. Its position vector after t seconds areI need instructions on solving this
  10. G

    Force Vector Accuracy: Building Bicycle Racks

    I am trying to build a couple bicycle racks and need help confirming that I got the forces right. The area in question is at the bottom assuming the reaction force will be to the right for the matter of balancing the moment. It's been a while since I took classical physics, so please correct me...
  11. W

    Using force vector to integrate work in xy-plane

    Hello, I picked up a challenging problem (at least to me) and I'm having difficulties. 1. Homework Statement An object moves in xy-plane from point O = (0; 0) to point A = (1 m; 0) and from there to point B = (1 m; 2 m). All this time when the object moves a force \vec F = ax2\vec i + by\vec...
  12. H

    Experimental Design - Measuring Force Vector on Cable

    Hi All, I'm trying to design an experiment for measuring force along a cable. The cable is will be held in a persons hand and the other end will be fixed to a transducer to measure the force of tension. In order to account for the multiple force vectors, I thought of using a gimbal table or...
  13. J

    Force Vector Magnitude Distance

    Homework Statement A force of f= i + 2j- 3k is applied to a particle that moves 10 feet in the direction of i + j. How much work is done? Homework Equations W= ||F|| dot product d The Attempt at a Solution D= 10 cos 45 i + 10 sin 45 j D= 5sqrt(2) i + 5 sqrt(2) j F= i + 2j - 3k...
  14. A

    Physics 3-D Force Vector Question

    Homework Statement Determine the magnitude of the projected component of F1 along the line of action of F2, if the cables each exert a force of 410 N on the post. The attempt at a solution I know how to figure out F2x, F2y, and F2z, but I have no idea how to find F1y and F1x. Also, what does...
  15. O

    What is the magnitude of force vector?

    1. Determine the magnitude of F2 2. How can I find this one force if I know resultant force and other force? Never done this before, that's why I've no idea. 3. Sorry, I have none.
  16. M

    Calculating Force Vectors Between Charged Particles

    Homework Statement http://imgur.com/opD71 Q1 = -2 C Q2 = 3 C Decide the forcevector F Homework Equations F = (k*Q1*Q2)/r^2 k = 8,99*10^9 Nm^2/C^2 The Attempt at a Solution Q1, Q2 = squarerot(5+7) = 9,24 mm = 0,924 cm = 0,00924 m F = (8,99*10^9*-2*3)/0,00924 = -5,838 * 10^12 N...
  17. P

    Help force vector problem

    help !force vector problem A cricket ball has weight 1.6 N. At any instant between being struck by the bat and reaching...? the ground the ball is subject to a resistive force of constant magnitude 0.5 N. (I have solved the following part with inverted commas but I am mentioning it case it be...
  18. A

    Finding components of a force vector given length components of vector

    Homework Statement A horseback rider is pulling a log behind him attached via a rope. The force of tension along the rope is 2000 N. What are the vector components of this force given the length components of the rope? The length components are x=1.5m y=2m z=2m. This problem is 3D so there are...
  19. T

    Force vector in a new coordinate frame?

    Homework Statement http://img811.imageshack.us/img811/9092/captureykj.png The Attempt at a Solution The answer is also in the image above. I have no clue how to start this question. Could anyone be so kind to give me a hint on how I should approach this question? Thanks!
  20. M

    Electric Force Vector Problem

    Homework Statement http://postimage.org/image/y4h1ubp8b/ Homework Equations F_xy=(k*q*q)/r^2 The Attempt at a Solution This is a problem involving Electric Force: http://postimage.org/image/y4h1ubp8b/ My goal is to find the direction and magnitude of q1. However, every...
  21. A

    Calculate the angle between the displacement vector and the force vector

    Homework Statement A force F = 8i-3i N acts on a particle that undergoes a displacement Δr = 2i + j m. (b) What is the angle between F and Δr? (state your answer to three significant figures) Homework Equations Angle = cos-1 (A.B/ AB) The Attempt at a Solution W=13.1 J AB=...
  22. F

    Calculating Resultant Force and Acceleration in a Simple Vector Problem

    Homework Statement A child has weight 450 N. Whilst on a fairground ride the child is subject to a force P acting at 35° to the upward vertical, as shown in the diagram. Given that the resultant of P and the child’s weight acts horizontally, a. Find the magnitude of the resultant b. State...
  23. N

    Force vector on falling object to determine terminal velocity and to graph it

    Homework Statement k: constant v: velocity m: mass g: gravity Homework Equations Vt= √(2mg/CρA) F=ma The Attempt at a Solution part a. part b. I do not know if i am doing this right and i do not understand how to do part c. If you know how to do this please explain
  24. E

    Force vector mulitplication = work

    Homework Statement F = 3x-y+2z in Newtons the line that it follows is -x+y+2z What is the work done Homework Equations W=f*d The Attempt at a Solution I am guessing 3x^2 -y^2+2z^2=w
  25. V

    Finding force vector fields for 3 dimensional potential energy fields

    Homework Statement Find the force vector fields (in terms of x, y, z, and any constants) for each of the following 3-dimensional potential energy fields Question B: Assume SI units for force, energy, and lengths x, y, z: What must be the units of each of the constants? Homework Equations a)...
  26. H

    What is the magnitude of the acceleration?

    Homework Statement This was an exam question that one of my friends recently had. Two horizontal forces act on a 32.5kg object. The first force has a magnitude of 210N and points in the direction 40.0 degrees East of North. The second force has a magnitude of 350N and points in the...
  27. 1

    Finding the force vector of an object with angular velocity

    So let's say i have two cubes. If one of them slams into the other (assuming it isn't moving at all) then the force vector is just going to be the direction the first cube was moving in correct? But say that this first cube also had angular velocity on some arbitrary axis, in other words it's...
  28. X

    Magnitude and direction of the net force vector

    Homework Statement The position r as a function of time of a 15.0 kg mass, moving in the x-y plane, is given by r(t) = (6.00t^3 x + 1.20t^4 y) meters where x and y are unit vectors. At t = 5.00 s, find the magnitude and direction of the net force vector which is causing this acceleration...
  29. Q

    How Do You Calculate the Correct Components of a Force Along Tether Lines?

    Homework Statement A resultant vertical force of 1750 N is necessary to held the balloon in place. Resolve this force into components along the tether lines AB and AC, and compute the magnitde of each force. The angle between AB and the vertical force is 40 deg, and the angle between AC...
  30. miraiw

    Force vector without acceleration

    This is just to see if I am totally confused or making sense. Homework Statement A truck is pushing up a hill on a 30 degree incline. It has a mass of 45 tons. Find the force vector for the truck. Homework Equations \vec{F} = ||F|| cos\theta i + ||F|| sin\theta j The Attempt at a...
  31. S

    Calculating Work Done Using Force Vector & Distance

    Homework Statement A constant force F=4i+2j+2k moves an object along a straight line from the point (1, -5, 1) to the point (1, -1, 0). Find the work done if the force is measured in Newtons and the position is measured in meters. Homework Equations W=FdThe Attempt at a Solution I used the...
  32. M

    Force vector - Value and uncertainty for components

    Homework Statement A force in polar coordinates is given by F1 = 50±2 N at the angle 30±2 degrees. Find the value and uncertainty for Fx and Fy Since force is a vector, there will be an error in both its magnitude and direction... angle calculations must be in RADIANS... 30\frac{+}{}2...
  33. L

    Finding the Angle and Magnitude of a Resultant Force using Vector Addition

    1. If the resultant force acting on the bracket is to be 790N directed along the positive x axis, determine the magnitude of F 2. Basically I got the components of the two vectors above and below F summed them up. I got THE RESULTANT X-component: 600cos45+325(5/13)+790cos(theta)...
  34. C

    Force Vector Directed Along A Line

    Homework Statement As shown, the cable OA exerts a force on point O of F = Fx(i) + Fy(j) + Fz(k). If the cable's length is a, what are the x, y, and z coordinates of A in terms of a, Fx, Fy, Fz. Homework Equations The Attempt at a Solution I am really not sure how to go about this. Please help!
  35. N

    Gravitational Force Vector exerted by 2 charged objects

    Homework Statement Two thin hollow plastic spheres, about the size of a ping-pong ball with masses (m1=m2 = 2e-3 kg) have been rubbed with wool. Sphere 1 has a charge q1 = -4e-9 C and is at location < 40e-2, -20e-2, 0 > m. Sphere 2 has a charge q2 = -6e-9 C and is at location < -50e-2, 40e-2...
  36. D

    Force Vector Problem: Find Magnitude & Direction of F3

    Homework Statement Three forces are applied to an object, as shown in the figure. Force F1 has a magnitude of 26.8 Newtons (N) and is directed 30.0° to the left of the +y axis. Force F2 has a magnitude of 15.2 N and points along the +x axis. A third force F3 is applied such that the vector...
  37. Mentallic

    How can I solve force vector mechanics without advanced concepts?

    Homework Statement http://img41.imageshack.us/img41/6579/mechanics2.jpg Homework Equations w=\frac{d\theta}{dt} (1) v=rw (2) F=ma (3) a=\frac{v^2}{r} (4) The Attempt at a Solution For (i), from (2) and (4) I get a=rw^2 and I'm thinking r=\frac{F}{cos\theta} but I'm not...
  38. S

    Coulombs law and vectors, find the force vector

    This is probably really obvious but I have a hard time with vectors and really don't know what it's supposed to look like..I'm not even sure if to draw the grav. force vectors starting from the ends of the ropes or straight down from the centers of the bullets. Homework Statement Two...
  39. E

    Force Vector Problem: Find Magnitude of Force on Rider from Motorcycle

    Homework Statement A motorcycle and 67.0 kg rider accelerate at 3.2 m/s2 up a ramp inclined 10° above the horizontal. What is the magnitude of the force on the rider from the motorcycle? Homework Equations I set my 90 degree axis so that my x-axis lined up with the acceleration up the...
  40. E

    Potential energy of a force vector

    If F is a conservative force, written in terms of a vector: F = kx i + ky j + kz k where k is a constant, How do i find the potential energy? I know how to use partial derivatives, but I am not sure how to integrate a vector. Please Help.
  41. M

    Force Vector Problem with Friction

    Never mind, I figured it out. Thanks!
  42. H

    Force Vector into a Force (Power)

    Homework Statement Find the power input of a force vector F acting on a particle that moves with a velocity vector v for each of the following situations. (a) vector F = 4 N i hat + 3 N k hat , vector v = 9 m/s i hat Homework Equations P = F * V The Attempt at a Solution P =(4*9) +3 Also...
  43. R

    Forces on an object, Force vector

    There are two forces on the 1.1 kg box in the overhead view of Fig. 5-37 but only one is shown. The figure also shows the acceleration of the box. IMAGE : http://www.webassign.net/hrw/05_37.gif (a) Find the second force in unit-vector notation. N i + N j (b) Find the second force...
  44. B

    Point Charges and Force vector addition

    Hi. I would appreciate some help with this point charge problem. I think I understand the general set up, but don't know where to go from there. Homework Statement Two point charges are placed on the x-axis as follows: Charge q1 = +4.00nC is at x=0.400m, and charge q2 = +2.00nC is at...
  45. H

    Deriving Vector and position vectors from Force vector

    Homework Statement An object of mass m is at rest at equilibirum at the origin. At t=0, a new force \vec{F}(t) is applied that has components F_{x}(t) = k1+k2y F_{y}(t)=k3t where k1, k2, and k3 are constants. Calculate the position r(t) and velocity v(t) vectors as functions of time. Homework...
  46. G

    Electric Force vector components

    [SOLVED] Electric Force Homework Statement http://session.masteringphysics.com/problemAsset/1001926/10/knight_Figure_25_46.jpg What is the force F on the 1 nC charge at the bottom? Write your answer as two vector components, separated by a comma. Express each component numerically, in...
  47. I

    How to Rotate a 3D Force Vector to Align with Another?

    Hello How do I manipulate (rotate) one 3D force vector so they are relative (in the same plane) as another 3D force vector please. First I have is a static reference vector SF that is the accelerometer stationary at some orientation. Next I rotate the accelerometer around one or more axis...
  48. M

    Solve 100J Torque Problem with a 30cm Wrench and Force Vector

    A wrench 30cm long lies along the positive y-axis and grips a bolt in the origin. A force is applied in the direction < 0; 3; -4 > at the end of the wrench. Find the magnitude of the force needed to supply 100J of torque to the bolt. how can i solve it? r=<0,.3,0> F=<0,3,4> T= r X F...
  49. D

    Find Force Vector for Given Position & Torque

    I am having a huge problem trying to answer the following question: Given the position vector r = 3i + 4j + 5k and torque = 16i - 20j - 5k, find the force vector F which will give the correct result, so that torque = r x F Can anyone please help me solve this!:confused: