Force Definition and 1000 Threads

  1. A

    I Conversion of Fluid Rotational Force to Rocking Motion

    Does anyone know how to convert the parameters within constraints to equate rocking motion from fluid being mixed through consistent shaking? What I am given: Centrifugal Force Calculations: mass = 0.25 kg angular velocity = 12.57 rad/s radius = 0.045 m What is known about the bag of fluid on...
  2. I

    I Resulting force on a chamfered pneumatic piston

    I was reading up on forces on hydraulic/pneumatic cylinders, and I've been thinking of this for a while: So for a pneumatic cylinder, the force on the piston is simply: P = F/a F = P x a where a = area of the piston that the air pressure is acting on. So what would happen if the piston is...
  3. R

    I am calculating the forces on String cheese with net force = 0

    Here is the link to the question. https://www.khanacademy.org/science/physics/forces-Newtons-laws/Newtons-laws-of-motion/a/what-is-Newtons-second-law What is the magnitude of the force F1 ? What is the magnitude of the force F2 ? Here is my drawing I made At this step I am lost. ## ay...
  4. A

    B Newton's second law of motion -- Why is it F=m*a and not F=m+a?

    Why F=m*a i.e product or multiplication and not F=m+a? i.e addition or summation?
  5. Eobardrush

    Why momentum of a ball bounced off a wall increases twice fold?

    Question 2a: It is really hard for me to get my head around this. The solution of this question mentions the momentum of the ball after it rebounds is 12kgms. My attempt at this solution is as follows Before collision Momentum of ball= mv= 2x3= 6 kgms and momentum of wall= 0 Therefore Total...
  6. D

    Magnitude of force acting on wedge and block

    Clearly if ##F = 0## and ##\tan\theta > \mu_s##, then using the above equations for ##f_s## and ##n##, we get ##f_s > \mu_s n## so the block will slip. However, it seems that as long as the force ##F## is directed to the right with a certain minimum magnitude, namely ##\frac{\tan\theta -...
  7. Lunct

    B Gravitational Force acting on a massless body

    It's a well known fact that acceleration due to gravity is independent of the mass of the accelerating body, and only depends on the mass of the body it is accelerating towards and the distance from it. One can prove this mathematically very easily. F=GMm/r^2 (equation 1) but also F=ma...
  8. F

    I Mechanical power generated by a force F

    Hello, It is well understood that a constant horizontal force ##F_{applied}## applied to an object of mass ##m## over a distance ##d## in a direction that is not orthogonal to the direction of motion produces mechanical work ##W= F d ##. This work is a mechanism to inject (or subtract) energy...
  9. O

    I Fluid force from a fluid flow vs. from a fluid jet

    In fluid flow (such as wind), the force exerted on a perpendicular surface is derived from kinetic energy and is ρAv^2/2. But in problems involving a jet of fluid that strikes a plate, the force is derived from momentum and is explained to be ρAv^2, lacking the 1/2 factor. Can someone please...
  10. A

    B Is the weak nuclear force attractive or repulsive or both?

    Hi Of the 4 fundamental forces, I did not understand the weak nuclear force. Is the weak nuclear force attractive or repulsive or both? It works between two particles, that is, it is the interaction of two particles?
  11. LCSphysicist

    Electric force due to a moving charge

    I am having some problems involving the force that a source moving with speed v along the x-axis would exert on a test charge at the x axis. Moving to the frame of the source charge, we got that the electric field it exerts is $$E' = kq/x'²$$ Now, moving back to the lab frame, and considering...
  12. I

    Calculating the Force of a Jump on the Moon

    From my understanding, at an elementary physics level, the height at which we can jump depends on acceleration due to gravity and the initial velocity when we leave the ground. We can calculate our initial velocity by calculating acceleration and using the distance we bend down before jumping to...
  13. D

    Friction force on each foot and on each hand of a person

    I get how to solve (a); my method involves finding the net torque about the man's hands and setting it to zero, which can be used to solve for the normal force acting on his feet and the normal force on his hands can be solved using Newton's first law. Then divide by 2 for each to get the normal...
  14. kara123

    Finding Friction Force & Work with No Applied Force

    -i had begun by finding the normal force =147 N -then found the force of friction=99.96 N -found the work of friction=-799.68 J after that I am unsure of where to go since I don't have a force applied
  15. G

    B Resultant force in vertical circular motion

    Suppose we have a vertical circular motion with gravity according to the image below. In the leftmost and rightmost positions the resultant force is pointing diagonally down. Isn't the resultant force supposed to be pointing at the center at all times in a circular motion? What am I getting...
  16. S

    Finding the position of a middle charge to have Zero Net Force

    Hi! Given three voltages as follows; Q1 = 1C,Q2 = 1C,Q3 = 2C The distance a is 1m and b = 2m a) Find the values of the forces that are acting on Q2 I did that like this; $$ F_{12} = \frac{Q1*Q2}{4\pi\epsilon r^2} $$ $$ F_{32} = \frac{Q1*Q3}{4\pi\epsilon r^2} $$ The results are ...
  17. Hamiltonian

    Force between charged Ring and Rod, disproved Newtons 3rd law?

    This is the initial setup of the problem: The electric field due to the ring is: $$E = \int\frac{k(dq)}{(\sqrt{R^2 + x^2})^2}\frac{x}{\sqrt{R^2 + x^2}} = \frac{kqx}{(R^2 + x^2)^{3/2}}$$ the force on the rod due to this Electric field produced by the ring is: Consider a differential element...
  18. S

    How Does the Direction of Normal Contact Force Affect Shelf Stability?

    Judging from FBD of the shelf, the answer will be either (B) or (D) because there should be horizontal force to the left to balance the horizontal force to the right by F, and by considering the torque, I think the answer will be (B) But I am confused about the direction of the normal contact...
  19. T

    Force on submerged plate perpendicular to flow

    Hey, I wonder how I can calculate the force of a plate that is submerged in water. I thought maybe the drag equation would be suitable for this with the drag coefficient set to 1.28 (https://www.grc.nasa.gov/www/k-12/airplane/shaped.html). But is implies the flow is according to the image...
  20. Z

    Understanding the electric force felt by the charges on a sphere

    A thin shell in reality doesn't have zero thickness. Consider the image below, showing a cross-section of a small portion of the shell: Here we are considering a more general case in which we have electric fields of magnitude ##E_1## and ##E_2## on each side of the shell. Gauss's Law...
  21. F

    Engineering Finding the force acting on a point charge with a disk around it

    Question: Here's my attempt with the relevant equations: The correct answer is F = -99.4 az μN. Could someone please figure out my mistake?
  22. S

    How Do Electromagnets Repel Each Other in a Zero-Resistance Environment?

    Consider 2 similar solenoids/electromagnets with appropriate iron core with the following parameters: core Length (L), core Radius (R), electromagnet wire diameter (w), number of turns of wire/winding layer on the core (L/w), number of layers of winding (K), total number of turns ((L*K)/w)...
  23. D

    Effect on net torque and net force on spools

    I think both spools will land about at the spot x (there aren't any horizontal forces causing them to land away from the x). Also, I think student 2 might be the closest to being correct, but I'm not sure if they're entirely correct; isn't it possible that force doesn't only go to translational...
  24. rudransh verma

    Confusion with force components

    x component of ##F_3## ##F_{3x}= m a_x- F_{1x}-F_{2x}## = ##ma\cos 50-F_1\cos(-150)-F_2\cos90## y component of ##F_3## ##F_{3y}= m a_y-F_{1y}-F_{2y}## =##ma\sin50-F_1\sin(-150)-F_2\sin90## And so on… My question how we can represent it in diagram ##F_1\sin(-150)##. I suppose...
  25. Iwanttolearnphysics

    About steel balls of different masses and net force

    I don't understand why the answer is B. Here's my thinking: Since it wasn't mentioned that there's any other force aside from the drag force, then Fnet = Drag force I know that Fnet = ma, and since they have different masses, Fnet must be different for both balls? Acceleration cannot be...
  26. F

    How a force is amplified in a lever from the standpoint of internal stresses?

    Hello, While trying to understand how a lever truly works and a force can be amplified using a larger lever arm, I read a thread on how levers amplify forces (https://physics.stackexchange.com/questions/22944/how-do-levers-amplify-forces ) and the discussion involves stresses, internal torques...
  27. A

    I Normal force and details of the Earth holding up an object

    It's a simple application of Newton's third law to show that the Earth indeed does accelerate towards an object as it falls towards earth. M_o is the mass of the object M_e is the mass of the earth From the third law (and ignoring air drag): M_e * a_e - M_o*g = 0 (with a up-positive...
  28. vibha_ganji

    B What Happens When The Applied Force Equals the Static Friction Force?

    In my teacher’s notes, it said that when the applied force on an object equals the maximum static frictional force, the object begins to move at constant velocity. My question is if both the applied force and the frictional force cancel as they are equal in magnitude, what force accelerates the...
  29. kara123

    Newton's laws of motion -- Force of gravity on a skydiver

    I think you would do force of gravity= mass x acceleration acceleration of gravity= 9.8 m/s mass 75 kg 75kg x 9.8 m/s =735 N i don't know if that's right but i have no idea how to calculate it after he lands, any help would be greatly appreciated!
  30. jonas_biermann

    B Calculating the torque needed to rotate a drum

    Imagine this: You have a drum with a radius of 12cm, around that drum is a toothed belt which is connected to a motor. The drum weighs 10kg The motor should be placed under the drum How would I calculate the amount of torque needed to rotate the drum I don't have any idea how to calculate this...
  31. DadoNoah

    Calculating force on a syringe plunger for a viscous fluid?

    I'm currently working on a precise glue/resin dispenser, and I'm trying to derive an equation for the force one must exert on a syringe plunger as a function of the desired flow rate Q, and also accounting for the fluid viscosity and the syringe barrel and needle geometry. I've attached a scan...
  32. I

    Lab Experiment - Puck Impact on Wall, Analyzing Force

    Please see attached image. This was a lab performed where a puck hit a wall shown on the page, the difficulty I’ve had is being able to see when and for how long the puck hit the wall as it is needed to find the average force in the system. Each dot on the page is 30milliseconds apart.
  33. lela

    Is the force exerted by a pivot always towards the center of mass?

    I thought that the force by the pivot A on the pole AB would be the reaction force to the x-component of the gravitational force on AB. This would mean that the force by the pivot would be parallel to the pole, but in my notes from class the force vector seems to be more along the bisector of...
  34. Z

    How to calculate differential work done by a force in circular motion?

    My question is, is this correct, and if so, why the minus sign?
  35. Induana

    Gravitational force equals centrifugal force?

    Book says that correct answer is d) but I can't understand why. If the result of gravitational and centrifugal force is 0N then there is no force that would keep those objects inside the spacecraft orbiting around the planet. Or am I just completely wrong? Thank you for your help.
  36. Elementrist

    B Magnetic force driving a small iron ball

    How can I calculate the force from magnetic field of a solenoid, grabbing a small iron ball? I want to use the good old simple F=ma formula in order to calculate the ball's acceleration. But can't find a formula to somehow convert the known field quality (in unit Tesla) to Force (in unit...
  37. Dezzi

    Electric field problem -- Repulsive force between two charged spheres

    I attempt to solve the problem in the picture below.
  38. S

    Bobsled Impulse and Force -- ELASTIC collision problem

    I attempted to do mvf-mvi to find the impulse, but had trouble figuring out what to use as v (where does the angle of 3degrees come in?), and thought that there had to be more to the problem considering the other details I was given. I then attempted to maybe calculate the kinetic energy lost...
  39. S

    I Gravity: Force or Acceleration?

    I’ve watched a few videos recently that explained that gravity is not a force rather it is caused by time dilation because clocks tick slower closer to mass. Objects will follow a geodesic through spacetime and require a force to move them away from a geodesic - so the surface of the Earth is...
  40. P

    Understanding the Coriolis Force: How to Calculate It

    I know that the perpendicular force is the Coriolis force, but I don't know how to get it
  41. V

    Force acting on a charge across a hybrid medium

    The force on charge ##q_2## will depend on the electric field in medium with dielectric ##K_2##. Electric field in this second dielectric due to ##q_1## is ##E = \dfrac {kq_1} {K_2r^2}## where r would be the distance from ##q_1##. So, the electric field at the point where charge ##q_2## is...
  42. D

    Seemingly simple equilibrium problem - force balance

    For this problem we are asked to find the tension in the cable BE and the compressive force in beam CE. We are given that ## \angle C = 40 \circ##. We are also given that CE = 10 meters and vertical BC = 6 meters. My solution is to find BE using the law of cosines, from which I get $$BE =...
  43. j19063dc

    Finding the resultant force, moment, and x-y coordinates

  44. K

    A Cyclic coordinates in a two body central force problem

    (Goldstein 3rd edition pg 72) After reducing two body problem to one body problem >We now restrict ourselves to conservative central forces, where the potential is ##V(r)## function of ##r## only, so that the force is always along ##\mathbf{r}##. By the results of the preceding section, I've...
  45. S

    I Base Motion and Vertical Beam - Basic Reaction Forces?

    So I am trying to understand how to estimate the amount of deflection [D] the vertical beam shown above would experience if the base it is attached to is accelerating at a constant acceleration [a] of 9.81 m/s. I assume the Force [F] would be equal to weight of the vertical beam (mass x...
  46. Nick Tucker

    Calculating Force and Work for a Penguin Climbing up an Ice Slope

    Got a question from my science exam that I'm not sure how to figure it out. All the context I was given is attached. My attempt: Mass=26kg 26a = Force Work = 26a x 2 Work = 52aNot sure how to figure it out, as 52a is the wrong answer.
  47. Rusty_Shackleford

    Push/Pull Force of wheeled cart on an incline

    Summary:: Looking for the formula to calculate force required to push a wheeled cart weighing 227 kg up a 15 degree incline. I’m trying to find the formula for force required to push a 227kg cart with four wheels up an incline that is 15 degrees. From my physics classes I thought the formula...
  48. D

    Maximum force applied to prevent block from sliding up ramp

    I tried using Newton's first law as the net force in both the x and y directions should be zero in this case. In the free body diagram you need to consider weight, friction, normal force, and the horizontal force. I got a result that said that the horizontal force F you apply is at most W(mu_s +...
  49. M

    I Build Setup to Create Electric Damping Force

    Hello! Is it possible to build a setup (containing time dependent and independent electric fields), such that a charged particle will feel a force proportional to its velocity i.e. ##ma = -\alpha v##?
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