What is Apparent weight: Definition and 71 Discussions

In physics, apparent weight is a property of objects that corresponds to how heavy an object is. The apparent weight of an object will differ from the weight of an object whenever the force of gravity acting on the object is not balanced by an equal but opposite normal force. By definition, the weight of an object is equal to the magnitude of the force of gravity acting on it. This means that even a "weightless" astronaut in low Earth orbit, with an apparent weight of zero, has almost the same weight as he would have while standing on the ground; this is due to the force of gravity in low Earth orbit and on the ground being almost the same.
An object that rests on the ground is subject to a normal force exerted by the ground. The normal force acts only on the boundary of the object that is in contact with the ground. This force is transferred into the body; the force of gravity on every part of the body is balanced by stress forces acting on that part. A "weightless" astronaut feels weightless due to the absence of these stress forces.
By defining the apparent weight of an object in terms of normal forces, one can capture this effect of the stress forces. A common definition is "the force the body exerts on whatever it rests on."The apparent weight can also differ from weight when an object is "partially or completely immersed in a fluid", where there is an "upthrust" from the fluid that is working against the force of gravity. Another example is the weight of an object or person riding in an elevator. When the elevator begins rising, the object begins exerting a force in the downward direction. If a scale was used, it would be seen that the weight of the object is becoming heavier because of the downward force, changing the apparent weight.The role of apparent weight is also important in fluidization, when dealing with a number of particles, as it is the amount of force that the "upward drag force" needs to overcome in order for the particles to rise and for fluidization to occur.

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  1. Mohmmad Maaitah

    How to calculate Apparent Weight of a passenger in a car going over a bump?

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  2. S

    Apparent weight problem (kinematics + conservation of Energy + Newton's laws)

    Hello there, I have tried the problem but don't get a different of 6g's as I am supposed to. I am not sure whether I interpreted the problem in the correct way, but I would love some feedback/hints on what went wrong in my solution, thanks in advance. Solution: SITUATION DRAWINGS + FBDS so...
  3. J

    I Apparent Weight problem (falling beam)

    Each weight: 2 Kg Hello All, I'm trying to understand an "apparent weight" problem and check my answer. Please use the picture attached. A weightless beam is at first resting over my palm, it has one 2 kg weight on each end of it. It is suspended to the ceiling by a rubber band. I drop it and...
  4. B

    B What is my apparent weight in water?

    Hi, I was wondering, what is my apparent weight in water? For example, when I tiptoe on land, my calf muscles are pretty much lifting all my body weight. But if I were to tiptoe with just my head out of the water, how much weight would my calves be lifting? And as I move to shallower water, how...
  5. S

    Speed and apparent weight of person in reverse bungee jumping

    a. To find the speed, I need to find the height where the cords first become loose, which is when the cord is 25 m long. $$h=30-\sqrt{25^2 - 5^2}$$ But the teacher's working is ##h=30-\sqrt{25^2 - 4^2}## How to get 4? b. My idea is to use Newton's 2nd law so I draw free body diagram of the...
  6. T

    Apparent weight of a body with upward acceleration

    I initially attempted to get the answer by multiplying the mass by 50, as I assumed if the upward acceleration was 5g then the weight could be found by just multiplying the mass by the acceleration of 50ms^-2. However that resulted in an answer of 3750 which was far below the correct answer of...
  7. brotherbobby

    Apparent weight of body immersed in liquid

    I have to assume that ##h## is the height of the body. The graph above shows how the apparent weight of the body changes as it is immersed into the liquid. In (a), after immersing the whole height of the body, the apparent weight ##W_{\text{app}} > 0##. Hence the upthrust ##U < w_B \Rightarrow...
  8. Kaushik

    Why does the apparent weight decrease when a body accelerates down a rope?

    When a body accelerates down(climbs down) a rope, why does its apparent weight reduce? Oh wait, does it even reduce in the first case? If yes, is it because of the Newtons first law of motion, which states that a body in motion tends to be in motion and a body at rest tends to be at rest. So...
  9. S

    Calculating the Ratio of Apparent Weight on a Ferris Wheel

    Homework Statement A Ferris wheel 26 m in diameter rotates once every 14 s. What is the ratio of a person's apparent weight at the top of the ride to her apparent weight at the bottom of the ride? Homework Equations [/B] FNT/FNB = mg - mv^2 / r / mg + mv^2/r The Attempt at a Solution...
  10. V

    What is the apparent weight of a woman riding over a hump in a car?

    Homework Statement A car traveling on a straight road at 9.15m/s goes over a hump in the road. The hump may be regarded as an arc of a circle of radius 10.4m. What is the apparent weight of a 665N woman in the car as she rides over the hump? Homework Equations ##F=ma##; ##a=v^2/r## The...
  11. A

    How Does Apparent Weight Change for an Astronaut Near the Moon?

    Homework Statement What is the apparent weight of a 70-kg astronaut 3800 km from the center of the Earth's Moon in a space vehicle when a) Moving at a constant velocity b) Accelerating toward the Moon at 2.9 m/s^2? State direction in each case Homework Equations wt = m(g+a) wt = m(g-a) Fgr =...
  12. Metalbob

    B About buoyancy and 2 equations

    1) My teacher says that the apparent weight of an object in water (floating,sunken,submerged etc) is equal to it's actual weight-buoyant force acting on it. That is, wt (ap)=wt (ac)- F(b) Where wt (ap) = apparent weight, weight (ac)= actual weight. And f (b) = buoyant force 2) But..., if an...
  13. A

    What is the difference between apparent weight and true weight in elevators?

    Homework Statement Hi everyone,I just want to know if my answers are correct. Homework EquationsThe Attempt at a Solution 1. For each situation, indicate whether the normal force exerted on you will be gater tha,less than or equal to your true weight. a) Elevator starts to move down from the...
  14. P

    True vs. Apparent weight question

    Homework Statement An astronaut in a rocket has an apparent weight of 1.35x103N [down]. If the acceleration of a rocket is 14.7 m/s2 [up] near Earth's surface, what is the astronaut's true weight? The acceleration due to gravity on Earth's surface is about 9.81 m/s2 [down]. Mass of Earth is...
  15. Frankenstein19

    Apparent weight loss 2nd Newtons Law elevator problem

    Homework Statement A 65-kg woman descends in an elevator that briefly acclerates at 0.20g downward when leaving a floor. She stands on a scale that reads in kg. (a) During this acceleration, what is her weight and what does the scale read? Homework Equations ƩF = maThe Attempt at a Solution I...
  16. Poquinha

    Calculating Density/Specific Body Mass: Need Help?

    If you have a body that weighs 200 N dipped in oil that has density equal to 0.8 g / cm³. This same body when immersed in water begins to weigh 60 N. How do I find the density / specific body mass? Already tried using the formula of the apparent weight = actual weight - buoyant and not worked...
  17. LesterTU

    Calculating Apparent Weight on a Rotor Ride

    Homework Statement A 30-kg child is on a rotor ride at a carnival. The radius of the rotor is 3 m and it completes 0.4 revolutions in one second. The coefficient of static friction is 0.6. What is the magnitude of the child's apparent weight? Homework Equations ΣFx : FN = mv2/r ΣFy : Ff = Fg...
  18. astrololo

    Calculate Apparent Weight at Point S

    Homework Statement When the train has passed at the point C, the radii of curvature is 20 m and the apparent weight is 2 2 times bigger than the real weight. At the moment when the picture was taken, the train was at the point s, located 8 m higher than the hollow C. At s, the radii of...
  19. DanielleG

    Centripetal Force Theory Questions

    Homework Statement Answer True, False, or Cannot tell to each of the five statements below. A small projectile is launched horizontally 1 m above the surface of a smooth, airless planet, with sufficient speed for orbit. A bug riding in a small hole in the projectile has apparent weight...
  20. T

    Apparent weight of a man standing in an elevator

    Homework Statement An 80.0 kg man is standing on a scale calibrated in Newtons inside an elevator. Determine the apparent weight of the man as shown by the scale as the elevator is a. stationary. [ans.785 N] b. accelerating downwards at a rate of 1.10 m/s^2. [ans. 697 N] c. accelerating...
  21. RJLiberator

    How Does Riding in a Cart at the Bottom of a Valley Affect Apparent Weight?

    Homework Statement A 60 kg person rides in a 20 kg cart moving at 13 m/s at the bottom of a valley that is in the shape of an arc of a circle with a radius of 36 m. What is the apparent weight of the person as the cart passes the bottom of the valley? Homework Equations F_centripital = m*v^2/r...
  22. L

    Apparent weight and kinetic energy

    Just wondering if apparent weight affects kinetic energy or is it only mass that affects it regardless of apparent weight? for example, a helicopter is falling but is providing a small thrust. say the helicopters mass is 50kg and it provides 100N of thrust upwards therefore, using w=mg, the...
  23. Maxo

    Understanding the Sign of 'g' and 'a': An Apparent Weight Example

    In my physics book the equation for apparent weight is given as FN = mg + ma where FN is the normal force, m is the mass of the object, g is the gravitational acceleration of the object (= 9.8 m/s2) and a is the acceleration of the system. For example the system could be someone standing on a...
  24. K

    What is the Apparent Weight of a Pendulum on a Trapeze?

    Homework Statement I am trying to determine the apparent weight while on a trapeze/pendulum. So far, I have heard that the apparent weight is either: a. the Fnet of all vertical forces (aka Centripetal force) and b. it is the force of tension. I am not sure which it is. Homework Equations a...
  25. A

    What is the Apparent Weight of an Iron Block Submerged in Water?

    Homework Statement The density of iron is 8 times larger than the density of water. An iron block has weight 800 N when it is weighed in air. When the block is weighed when completely submerged in water, the apparent weight is... The answer is 700 N but I don't know how this is determined...
  26. N

    Pilots, diving and apparent weight

    Homework Statement While pulling out of a dive, does a pilot's apparent weight increase or decrease? Homework Equations The Attempt at a Solution My instinct for this question says increase but only because of the feeling that I remember from being in planes. I'm trying to grasp...
  27. A

    Apparent weight of a pilot in a loop

    Here's a picture: Edit: Here's a description of the problem in case the picture isn't clear. A 54-kg pilot flies a jet trainer in a half vertical loop of 1200-m radius so that the speed of the trainer decreases at a constant rate. Knowing that the pilot’s apparent weights at Points A and C...
  28. A

    Apparent weight / Rotating coordinate system

    Homework Statement Show that, owing to the rotation of the Earth on its axis, the apparent weight of an object of mass m at latitude λ is : m((g-ω^{2}Rcos^{2}λ)^{2}-(ω^{2}Rcosλsinλ)^{2})^{1/2} where ω is the angular velocity of the Earth and R its radius. The first space travellers to reach...
  29. N

    Apparent weight in an elevator intuition

    Homework Statement The numbers aren't important because I'm after getting a more intuitive sense of the problem. When an elevator is accelerating upwards with a mass in it on a scale. Why is the apparent weight the normal force? Homework Equations F=ma W=mg The Attempt at a...
  30. C

    Finding Apparent Weight with Uniform Circular Motion

    Homework Statement A ferris wheel with a radius of 14.0 m rotates at a constant rate, completing three revolutions in 50.0 s. What is the apparent weight of a 60.0 kg passenger when she is at the top of the wheel? Given choices: 532 N, 452 N, 562 N, 625 N, 469 N Homework Equations...
  31. M

    Apparent Weight of Astronaut

    Homework Statement What is the apparent weight of a 730-N astronaut when her spaceship has an acceleration of magnitude 2.0g in the following two situations. a) just above the surface of Earth, acceleration straight up; b) far from any stars of planets? Homework Equations Fnet=N-mg=ma...
  32. T

    Proving that apparent weight is 5 times actual weight (no numbers)

    Homework Statement Without numbers, identify how you could find the apparent weight of motorcycle to be 5 times that of the actual weight. The motorcycle is going up a loop the loop with a velocity of v. Homework Equations Fnet = mv^2/r Fg = mg The Attempt at a Solution Fnet = mv^2/r...
  33. H

    Apparent Weight in a Spinning Space Station

    Homework Statement To simulate gravity, a circular space station with a radius of 150 m is rotated so that astronauts standing on the inner surface move at 30 m/s. If the 75 kg astronaut stands on a bathroom scale what reading will it give? (assume the scale is calibrated in Newtons)...
  34. T

    Apparent weight lab: oscillations and v(t) graph

    Homework Statement In a lab I collected data for change in apparent weight of a ~1kg mass during an elevator ride. The mass was suspended from the scale by doubled up rubber bands. This caused plenty of oscillations in the data. Can i apply the form mx"(t)+γx(t)+kx(t)=Fcosωt to this situation...
  35. S

    Apparent weight of immersed bodies

    Homework Statement An object has a weight of 250N, when weighed by spring balance. The same object is fully immersed in water, then the spring balance reading shows, 150N. How to determine the relative density of the object.Homework Equations Archimedes' principleThe Attempt at a Solution...
  36. Z

    Apparent Weight in an Elevator

    Homework Statement While stationary on Earth you have a weight of 550N. When in an elevator that accelerates upward your weight temporarily becomes 590N. When descending, your weight temporarily becomes 510N. Find a) the acceleration you experience as the elevator moves up and b) the...
  37. A

    A question about apparent weight.

    How to find the apparent weight of objects in a certain latitude? the formula of the apparent weight is R=mg-mrω^(2)cosθ? thank you~
  38. B

    Calculating Apparent Weight Difference Between Equator and South Pole

    Hello all, just a few problems that I've worked through, just clarifying if I'm on the right track. Thank you in advance. 1.) The radius of the Earth is 6378.1 km and completes one revolution per day. Calculate the difference in apparent weight between a person of 65kg mass, standing on the...
  39. B

    Why do we weigh less at the equator?

    Hello all, I was just bugged by the fact that you weigh more at either of the poles than you do at the equator. I reason that because at the equator you feel the Earth spinning about it's axis, you would feel an additional centripetal force toward the centre of the Earth ontop of the...
  40. B

    Apparent weight of a submerged rock.

    Homework Statement What is the apparent weight of a rock submerged in water if the rock weighs 58 N in air and has a volume of 1.8 * 10^-3 m^3? And then as a continuation: A rock weighing 57 N with a volume of 2.3 10-3 m3 is submerged in a liquid with a density exactly twice that of...
  41. W

    Rotation of the Earth and Apparent Weight?

    Homework Statement Because of Earth’s rotation about its axis, a point on the Equator experiences a centripetal acceleration of 0.034 m/s2, while a point at the poles experiences no centripetal acceleration. What is the apparent weight at the equator of a person having a mass of 118.1 kg...
  42. P

    Ship at Sea, Apparent Weight Problem

    Correct? Please let me know if my logic is off. Thank you =] Given Problem At the bow of a ship on a stormy sea, a crewman conducts an experiment by standing on a bathroom scale. In calm waters, the scale reads 180 lb. During the storm, the crewman finds a maximum reading of 234 lb and a...
  43. S

    Astronaut's Apparent Weight in Different Gravitational Fields

    Homework Statement What is the apparent weight of a 730-N astronaut when her spaceship has an acceleration of magnitude 2.0g in the following two situations: a) just above the surface of the Earth b) far from any stars or planets Homework Equations Wapparent=m(g + a) The...
  44. T

    Apparent Weight and Newtons Second law Problems

    Homework Statement 1. The first problem states that an elevator moves downwards with an acceleration of 3.36 m/s^2 with someone inside that has the mass of 64.2 kg. Now what is the apparent weight? 2. Blocks A and B are right next to each other. If 5.1 N were applied on block A, calculate...
  45. K

    Passengers apparent weight on elevator when it's acceleration is negative

    Homework Statement There's a 75 kg passenger in an elevator a. what is the passenger's apparent weight when acceleration is zero? b. what is the passengers apparent weight when acceleration is positive? c. what is the passengers apparent weight when acceleration is negative? Homework...
  46. S

    Weighing a Salmon in an Elevator: What's the Apparent Weight?

    Homework Statement A 5.0kg salmon is weighed by hanging it from a fish scale attached to the ceiling of an elevator. What is the apparent weight of the salmon if the elevator is (a) at rest, (b) moving upward at 2.5 m/s2, and (c) moving downward at 3.2 m/s2? Homework Equations Sum of F...
  47. S

    Very quick question about lift and apparent weight?

    Hello everyone, When you go down a lift, are you actually falling down. Is the lift carrying you down, or are you falling down due to gravity towards the lift, if the lift goes too fast would your head crash? Sorry if my thinking is completely wrong. Ok now apparent weight is from the...
  48. S

    Fluids Archimedes principle apparent weight question

    Homework Statement Vessel contains water.It is placed on the pan of a physical balance.A solid(specific gravity=1) is suspended from an thread(from an independent support),such that it is immersed completely in the water. What the weight it reads? If the thread was tied to the arm of...
  49. C

    Elevator Problem Apparent weight and distance traveled

    Homework Statement Henry gets into an elevator on the 50th floor of a building and it begins moving at t=0s. The figure shows his apparent weight over the next 12 seconds. Part A: Is the elevator's initial direction up or down? Explain how you can tell. Part B: What is Henry's mass...
  50. M

    Apparent weight - ferris wheel

    Homework Statement So if a person's apparent weight at the top of a ferris wheel is 0N find the time it takes the ferris wheel to make on rotation. Then find the apparent weight of a person at the bottom of the ferris wheel for the same person on the same ferris wheel?Homework Equations...
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