Weight Definition and 1000 Threads

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...

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

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...

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...

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...

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

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...

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.

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...

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...

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?

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...

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?

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...

In the Kallen-Lehmann spectral representation (http://en.wikipedia.org/wiki/K%C3%A4ll%C3%A9n%E2%80%93Lehmann_spectral_representation) the interacting propagator is given as a weighted sum over free propagators. The pole of the integracting propagator is, of course, given by p^2=m^2, m being the...

I'm doing an experiment and I have to calculate calculate rotational kinetic energy of this can rolling down an inclined plane. According to the equation, Er=1/2Iw^2, I=mr^2, and w=v/r (no slipping effect) right? but doesn't I=mr^2 apply only when the weight is evenly distributed throughout...

Homework Statement Vapor density of a metal chloride is 66. Its oxide contains 53% metal. The atomic weight of the metal is ? Homework Equations vapor density = 0.5 * molar mass The Attempt at a Solution Using the above formula, I found the molar mass of the metal chloride as...

Within an 18-21 gram range, can you produce more force when striking a cue ball with a lighter or heavier cue?

Homework Statement problem #62 Homework Equations Torque = F * radius Tangential accel = radius * alpha w = mg Kinematic equations for linear motion The Attempt at a Solution I tried to find the net torque and go from there. For clockwise torque I got T = 10 * .25 = 2.5 Nm...

If travelers sat on connected lawn chairs on wheels guided by rails pulled by a motor on wheels we might reduce the ratio of rail train weight to that of the weight of passengers carried. An Amtrak passenger train weighs about 200,000 lbs. and holds say 100, 200 lb. people, for a ratio of...

Homework Statement A weight (mass given) is sitting on a beam that is supported by two columns. Given the location of the weight on the beam, calculate the force on each column. Homework Equations not sure The Attempt at a Solution not sure

Homework Statement A study of weight gain in male rats compared two diets, A and B, which were formulated in terms of level and source of protein. A total of twenty two rats were randomly assigned to the diets, eleven to each diet. Summary statistics for the weight gains (grams) by the...

Suppose you put two weights at each end of a string or rope and then throw it away. As we all know the weights will circulate around the center of mass. Now the problem is what is the tension of the string. I am confused about this since there seem to be two contributions to the tension...

My name is Derek Cox, I am new to the forum and I am not an engineer or anything close. I have a degree in flight management and I am a commercial plumber that works on large scale construction projects. Here are my questions but first I will give you some background on the questions. I am...

when a can of coke placed in a sensitive balance is opened what happens to the reading? the answer of this question is given first increases and decreases. can anyone explain this?

Homework Statement An arctic hunter goes hunting polar bears and shoots one. He finds it lying dead on a large patch of almost frictionless ice. He has no scales or weighing device of any kind (and of course, there's nothing to hang it on) but he does have a long rope. How can he get a pretty...

I've read a few books on solving differential equations and they all talk about inner products with respect to weight functions. The examples always read something like that "Using the weight function w(x) = blah blah show that the solutions of the differential equations are orthogonal" We're...

How much weight would I have to carry to equal the resistance I would face swimming in a pool of water? Let's assume I am wearing the same clothing to perform both events.

I am 6'1" and weigh 180 lbs. I need to lose enough wait to get down to single digit body fat percentage. What do u guys recommend in order to lose about 10-20 lbs?

Ok So I have been wondering this for awhile. Could someone help me find an equation to figure this out. I play slowpitch softball and was curious about swing speed and the weight of the bat. If we keep the mass of the ball constant (.198 kg), and the pitch speed constant (8.94 m/s), and...

Ok So I have been wondering this for awhile. Could someone help me find an equation to figure this out. I play slowpitch softball and was curious about swing speed and the weight of the bat. If we keep the mass of the ball constant (.198 kg), and the pitch speed constant (8.94 m/s), and...

Dear native English speaking professionals! Would someone please advise on the term "gross weight load" - is it possible to use it for gravity force of a fully loaded railcar? I use it in the following context: "Estimated vertical force on one chord section is assumed to be equal to...

Hello Physics Forums! Longtime lurker, first time poster here. I've got a deceptively simple question that had my friends and me occupied (read: bickering) for quite some time during a road trip, and I thought I might pose it to you. The situation is this: we have a 2x4 piece of wood, and...

Homework Statement An air-conditioner unit is fastened to a roof that slopes upward at an angle of 36.0˚ . In order that the unit not slide down the roof, the component of the unit's weight parallel to the roof cannot exceed 520N. What is the maximum allowed weight of the unit...

I need to find the length, weight of the bob and angle to make the pendulum a complete revolution. Kindly help me.

I am needing a project to withstand the impact of a 15lb wood 2x4 traveling at 67mph in a horizontal fashion. I want to test my project before the final test. I want to vertically drop a 15lb wood 2x4 fixed to additional weight at a height of 10ft. The additional weight will be released just...

I've heard that losing weight does not decrease the number of fat cells your body contains. But does this number decrease if you maintain this lower weight over time? I'm thinking that over time, the fat cells die and are replaced at a lower rate.

Can you tell me what spectral weight is? If I have a spectrum that I measure, how can I get spectral weight? For simplicity, assume that the spectrum is a Gaussian curve. Thank you so much!

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~

I know it doesn't change mass, but does it change weight? Example: Let's say I put a weight sensor under the road as the car drives on it. Will it feel the same weight if the car stood still and if it drove really fast, or would it feel different weights?

Homework Statement A 43.0 Kg weight is suspended by 2 ropes (imagine a triangle with 〖40〗^0 / 〖30〗^0 angles) Find the tension in each rope. Homework Equations The Attempt at a Solution

Moment -- A weight on a plank Homework Statement A uniform plank of weight 120 N rests on two stools as shown in the link provided below. A weight of 80N is placed on the plank, midway between the stools. Calculate the force acting on the stool at A and B. The answer is 80N and 120 N...

Hello everyone! I am struggling with calculating the normal forces for a vehicle that is in contact with the ground at three places (scoop, front wheels, rare wheels). To calculate the normal forces with two locations (such as front and rare wheel) it is just to balance the forces as well...

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...

Homework Statement find the equation of state which gives the relationship between P , V , N and T C and b are constants Ω = CebNV2(EV)N Homework Equations P/T = (ds/dV)E,N The Attempt at a Solution so i just use s = klnΩ ? then i get ds/dV = k2bNV so P = k2bNVT ? that's it? btw, what...

Hello there, My name is Rick and a couple of my friends are having a discussion at a local rock climbing gym about the weight of a person and whether or not a person who is heavier, works harder than someone who is lighter. Neither one of us are gurus when it comes to physics but would love an...

I want to know the fundamentals of finding the force reqd for moving a stationary object such as a car or a segway (which has got two wheels). Also let me know in a formula mu = F/ NORMAL REACTION, WHAT IS THE VALUE OF A WEIGHT HAS TO BE TAKEN? meaning if weight of a person standing on a...

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...

Maybe I'm old-fashioned or stuck up or something, but this really bothers me, and it seems to be a growing trend that people gain weight and become flabby as they get older. To me this seems so disrespectful to your partner. A man or woman was attracted to you based on how you looked when...

Homework Statement The picture below shows a mobile in equilibrium. Each of the rods is 0.16m long and each hangs from a supporting string that is attached one fourth of the way across it. The mass of each rod is 0.10kg. The mass of the strings connecting the blocks to the rods is...