Weight Definition and 1000 Threads

  1. J

    Weight causing a wheel to rotate

    Homework Statement Homework Equations I_solidcylinder = .5mr^2 I_thinring = mr^2 torque = I*Ω (where Ω = angular acceleration) change in theta = .5(Ω)(time^2) The Attempt at a Solution Attempted to solve for angular acceleration: (2.5)(9.8)(0.1) = (3*0.25^2 + 0.5*4*0.1^2)Ω...
  2. G

    Chemistry What is the Molecular Weight of a Gas Using the Ideal Gas Law?

    [b]1. A 0.0097561 g quantity of an unknown gas occupies 0.2 L at 500 K and 2 atm. What is the Molecular Weight (MW) of the gas ? [b]2. PV = nRT [b]3. mw=0.0097561*0.082*500/2*0.2 mw=1
  3. A

    A non-uniform is 3.8-m long and has a weight of 560.-n.

    Homework Statement A non-uniform is 3.8-m long and has a weight of 560.-n. The bar is balanced in a horizontal position when it is supported at its geometric center and a 340.-n is suspended 0.70-m from the bar's light end. Sketch this system and find the bar's center of gravity...
  4. L

    Thermodynamics speed of a weight bar through ice

    Homework Statement A steel bar of rectangular cross-section, with height a and width b (into the paper), is placed on a block of ice with its ends extending a little beyond the ice, (ice has a length c). A weight of mass m is hung from each end of the bar. The entire system is at 0 degrees...
  5. C

    What Force is Necessary to Submerge Mary in Fresh Water?

    What force is necessary to just barely submerge (push Mary under fresh water) Mary if her average specific gravity is 0.95 after taking a deep breath and her weight in air is 660 N? F=mg ; Force of buoyancy=ρgV; F=mg 660/9.8=mass of air mass of air=67.3 force of buoyancy= 67.3 x...
  6. J

    Pascal's Law - Weight of Water Involvement

    Pascal’s Law states “pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio (initial difference) remains the same”. My question is, are the two scenarios that I have outlined the same? (see...
  7. V

    The total weight o a gas filled balloon is 1500N.

    Homework Statement The total weight o a gas filled balloon is 1500N.THE BALLOON RAISES AT CONSTANT SPEED OF 10m/s.Calculate the resultant force acting on the balloon? Homework Equations The Attempt at a Solution
  8. V

    Weight at different height forklift

    Hello I would like to know how to calculate the rated capacity of a forklift at different height? How can weight to be carried change as teh height increase...
  9. R

    Weight vs Speed: Which Generates More Force?

    If object A is more heavier and durable than object B, and both objects are traveling at the exact same speeds, which one would generate more force? I know it sound like a silly question, but I've learned that momentum equals impact force. So I was wondering if the extra weight and durability...
  10. H

    The weight of an object is 25kgf. What is it's mass if local gravity is 9.6m/s^2

    I've learned Kg to Kgf this time I got another question.. I think it's another way around.. "The weight of an object is 25kgf. What is it's mass if local gravity is 9.6m/s^2" Tried this.. 25/(9.6)(9.8)= 25.5kg
  11. S

    Atomic % & Weight % of Phosphorous in Solid Solution

    Homework Statement Given: 5x10^21 Phosphorous atoms/m^3 in solid solution in silicon Find: atomic percent and weight percent of Phosphorous atoms The Attempt at a Solution I know how to solve for at. % and wt. % when given two values, I am not sure how to get the second value given the...
  12. A

    Roller coaster cart gaining weight into a loop

    Homework Statement A roller-coaster car starts from rest at a high point 2 times as high as the top of the loop-the-loop. When it is just about to enter the loop from the bottom, a 100 lb bag of bricks fall on the car, causing it to lose 25% of its speed. Neglecting friction, do you think the...
  13. C

    Weight of a man orbiting this given planet

    Homework Statement The mass of one planet in a distant galaxy is 0.58 that of the Earth's mass , and its radius is 0.57 that of the Earth's radius. What is Fnew, the factor by which the man's weight is reduced if he were orbiting the planet at a distance of 3.5 Earth radii above the...
  14. F

    Calculate Dumbbell Counter Weight for Correct Exercise Position

    Homework Statement Hi all, First post so please go easy :smile: I am designing a Dumbbell support that presents the Dumbbell to the user in the correct exercise starting position (1. Shown on the image.) . The problem I am facing is the counter balance to the support. The Dumbbells range from...
  15. S

    Material strong enough to hold baby weight but cheap.

    I looking to make my own changing table to travel with. Want hard plastic material, non toxic that can hold baby weight. Any ideas?
  16. S

    Torque for rotating a shaft of unbalanced weight

    [b]1. Hi all. Can anyone please help me find the torque required for rotating a shaft which has two masses 1000 Kg each at 120 Degree angles. Please refer to the attachment for clarity. Homework Equations The Attempt at a Solution
  17. D

    Pilot problem dealing with weight and magnitude of force exerted on pilot's body

    Homework Statement The Pilot of an airplane executes a loop-the-loop manuever in a vertical circle. The airplane's speed is 300 mi/h at the top of the loop and 450 mi/h at the bottom. The radius of the circle is 1200 ft. Use American Engineering units in this problem. A) The pilot's...
  18. C

    Weight before/after change in rotation Speed

    Homework Statement How would the weight of a person in some place (48 North and 123 West) change if the rotation rate increased so a day was 3 hours long? Homework Equations F=ma The Attempt at a Solution The above is not the only equation I think that is needed for this. Not...
  19. I

    Equilibrium Question With Ropes and Weight

    Homework Statement Click on photo to enlarge The weight at the end of the rope is 1000 N. Find tensions in T1, T2, and T3. Homework Equations Law of Cosine: a^2+b^2-2ab(cosC)=c^2 SOH-CAH-TOA The Attempt at a Solution T1 has to be 1000N. I figured T2 and T3 have to add up to...
  20. H

    Why does the weight of opened cold coke change over time?

    A bottle of coke was taken out of refrigerator. It was then kept in a sensitive weighing balance.Its cap was opened. The initial weight was found to be 2.403 kg. After a while its weight increased to 2.423 kg. Then again it started decreasing. I repeated this experiment for many times. And the...
  21. G

    Cable breaking under its own weight?

    Homework Statement A scientist assembled large amount of cable. The longest piece of cable that is hung vertically and does not break under its own weight is of length k. He then places another piece of the cable on a friction-less table. A small part of the cable is hanging over one side and...
  22. B

    How to Calculate Net Force on Elevator Moving Downward with Upward Acceleration?

    Homework Statement A weighs 600 N on an elevator when it is stationary. Each elevator accelerates according to the specified arrow that is drawn next to it. In all cases where the elevator is moving, it is moving downward. Find net force, if the elevator is accelerating 2.0 m/s/s upward, even...
  23. H

    Weight of water in different vessels

    Water is poured to same level in vessels having different shapes. If pressure is the same at the bottom of each vessel, the force experienced by base of each vessel is same. Why then do these different shape vessels have different readings when placed on weighing scale?
  24. X

    Why weight on an incline is different?

    Hey guys, first post here... So, I'm having an issue comprehending this topic: Let's say you have a box which weighs 3 N, and you place a 7 kg block on top of it. So, since the block is laying on a horizontal plane, the weight is mg, or 6*10=60 N. Total weight=60+3=63 Let's say you have an...
  25. P

    What is a 68kg Person's Weight on Mt. Everest?

    Homework Statement Find a 68kg person's weight on top of Mt. Everest (8848m above sea level) Homework Equations The Attempt at a Solution
  26. A

    How to calculate weight an arm can curl.

    Homework Statement Suppose the length of your forearm is 34cm and its mass is 1.3kg. If your bicep inserts into the forearm 3.5cm from the pivot (the elbow), and your biceps muscle can produce a force of 800 N, how much weight can you curl? Model your forearm as a uniform rod. I have no...
  27. D

    Force done by the spring if a weight is attached

    Homework Statement What is the force done by the spring if an object of mass m is attached. Homework Equations F=ma F=-kx Fg=mg The Attempt at a Solution Sum F = 0 mg-kx=0 mg-Fs=0 Fs=mg Therefore the force done by the spring is mg? is the +/- right? for direction? Is the...
  28. P

    How much does a body weight in free fall?

    Homework Statement Well, that's all, my mid-term exam came a question that asked me: if a body with mass of 50 kg was weighed on a scale that is inside an elevator in free fall, how much will it weight? I supposed that the same it would weight on the surface, since gravity never stops...
  29. B

    Pressure required to lift a weight

    Assume all dims in millimeters and kilos and I am working on a hydraulic set up I have a cylinder Ø200mm diameter x 400 high, it has a hole in the middle Ø10mm going into a capped Ø10mm pipe. The cylinder is filled with water up to 300mm high. There is a bouyant weight that floats on top of the...
  30. M

    Engine cylinder weight and power

    Can anyone tell me if engine cylinder weight lowers, does it make change in fuel consumption or the power of engine?
  31. U

    Bar holding a weight (conceptual)

    A long, thin metal (massless) bar is rotating in a circle at constant velocity, perpendicular to the axis of rotation. A weight is placed on the end of the bar such that there is no vertical movement of the weight or bar. What force counteracts the force of gravity on the weight?.
  32. T

    Find the coefficient of Friction with weight and force needed to move and object

    Homework Statement A block weighing 9.3 N requires a force of 3.7 N to push it along at constant velocity. What is the coefficient of friction for the surface Homework Equations Ff=μ*Fn The Attempt at a Solution So the 3.7 N to push is the Force of friction so 3.7=μ*9.3...
  33. D

    How Does Weight Distribution Affect Wheel Spin Duration and Speed?

    If I make 2 wheels of identical size and weight, so that the only difference bewteen the 2 is that wheel A has most of its weight at the center of the wheel and wheel B has most of its weight equally distributed on the circumference of the wheel: 1. Which wheel would spin longer if both...
  34. 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...
  35. J

    Can Losing 10 Pounds Increase Your Vertical Jump by 2 Inches?

    Imagine an athelete that weighs 180 pounds (81.6 kg) is able to jump 20" (0.51 meters) vertically. How high could he jump if he were able to decrease his weight to 170 pounds (77.1 kg)? I think the basic idea here is to find out, given the mass, what force is required to reach the specified...
  36. G

    How can I lift more than my weight?

    There is a tricep machine which is basically a pulley, with some rope connected to a stack of weights and a bar for you to push down on using your triceps on the other end of the rope. How is it possible that if I'm 140 pounds, I can lift like 180 or more on that machine? If I want to want...
  37. nukeman

    Weight lifter - Acceleration of the barbell ?

    Weight lifter - Acceleration of the barbell ?? Homework Statement Here is the info, and below are the questions I am a little stuck on... "An athlese who mass is 90.0 kg is performing a lift exercise. Starting from the rest position, he vertically lifts a barbell weight that weighs 490N...
  38. B

    How does the atmosphere affect human weight on Earth?

    Does Earth's thick layer of atmosphere push down on us, increasing our weights drastically?
  39. J

    Due in an HOUR Early Physics problem relating drag, weight, and speed.

    Due in an HOUR! Early Physics problem.. relating drag, weight, and speed. Homework Statement A 1.74 m wide, 1.48 m high, 1500 kg car hits a very slick patch of ice while going 21.0 m/s. Air resistance is not negligible. If friction is neglected, how long will it take until the car's speed...
  40. S

    Finding the weight, work, and normal force of a block

    Homework Statement 4 questions: 1. A block of mass M=2.6 kg is dragged over a horizontal surface by a force F=22.0 N. The block is displaced a distance d=10.0 m, the friction force Ff is 3.1 N. What is the weight of the block in Newtons? Use 10 m/s2 for g. 2. A block of mass M=1.0 kg is...
  41. G

    Medical Gaining Weight: A Biochemical Perspective

    I thought about what gaining weight means. Isn't the following (obviously) correct? When you eat X grammes of something you momentarily gain X grammes of weight. The only way to lose weight is to go to the toilet or sweat. However, when you sweat most of the mass is water so this is easily...
  42. H

    Weight Fluctuations: Is More Weight Gained at Night?

    weight is more at night than day. is this right? if not why?
  43. D

    How to calculate weight of object swinging a radius?

    Homework Statement 20 lbs. on the end of a 30 inch arm. Dropping from 2oclock position to 5oclock position. How much wieght will be developed if this was dropped on a scale measuring lbs. Homework Equations I am unsure how to calculate this. The Attempt at a Solution If there is...
  44. P

    Stall Speed vs. Weight and Altitude

    Can someone explain how and why stall speed (TAS?) varies with aircraft weight and altitude? If you need equations to explain this, I can still handle algebra, but I have forgotten all of my college calculus! Thanks.
  45. K

    Finding weight using Archimedes' principle

    A rectangular block of solid carbon (graphite) floats at the interface of two immiscible liquids. The bottom liquid is a relatively heavy lubricating oil, and the top liquid is water. Of the total block volume, 54.2% is immersed in the oil and the balance in the water. In a separate experiment...
  46. O

    Will weight of flying mosquito in a jar affect its weight ?

    As a part of an experiment,..... a scientist put 100 mosquitoes in a jar and shut it... When he weighed the jar, while the mosquitoes were sleeping on the base of the jar, the weight came out to be 250 g... Then, he shook the jar and the mosquitoes started flying inside it. He once again...
  47. K

    Understanding the Balance: Equal Weight, Unequal Position

    Confused about a simple thing... For a common balance, since both arms have equal weight, what causes the pole to choose a horizontal position? Shouldnt it be stable in any other position as the torque around the centre is zero for any other position too?
  48. Z

    What is the Apparent Weight in an Accelerating 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...
  49. A

    Mass and Weight - which do scales show?

    Whenever you step on a scale, digital or spring, is that your weight? Or has the scale been calibrated to take into account the Earth's gravity and the number shown is your mass?
  50. B

    Discovering the Truth: Dead Weight vs. Live Weight in Cats and Humans

    My cat died recently and both my daughter and I were amazed at how much heavier he was dead than alive. I have read the posts on this website about live "dead weight" (The boy who found his sleeping sister to be much heavier to carry than when she was awake.) But the answer does not seem...
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