Weight Definition and 1000 Threads

I'm browsing through some acceptances posted by prospective graduate students here: http://www.physicsgre.com/viewtopic.php?f=3&t=4274 and there are some guys with very close to 4.0 GPAs and great GRE scores along with pretty good research experiences and letters of recommendations that are...

Homework Statement Julie tightened herself fastened a set of bathroom spring scales to a platform and went down a 30 degree slope. No friction was present and the platform supporting the scales was HORIZONTAL. what fraction of her true weight was indicated by the scales? The Attempt...

Homework Statement A man is flying a kite. The string of the kite makes an angle of 50 degrees with respect to the horizontal and exerts a pull of 15 Newtons. A small bird decides to sit on the kite and causes the kite to reach a new equilibrium position with the sting at 30 degrees with...

I know this question maybe a bit funny, others will call this post BS. But just assume if any object, having a size that ten times larger than Earth and having infinite weight, can the Earth resist such pressure? I recalled somewhere mentioned that Earth, theoretically, can support weight...

Homework Statement http://data.imagup.com/10/1146555432.jpg Homework Equations Force applied on the weight=F*(MA). The Attempt at a Solution i chosse the E system ...it has the greater mechanical advantage (MA)=3. MA(of A)=1, MA(of B)=2,MA(C)=2,MA(D)=2,MA(E)=3.. I hope my...

Weight on a Scale Down an Incline vs. True Weight Homework Statement Judy fastened a set of bathroom spring scales to a wedge shaped skate board as shown and coasted freely down a 30 degree slope. The wheels were well oiled and the platform supporting the scales was horizontal. What...

Homework Statement http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2008_QP.pdf Question 8 Homework Equations f=ma The Attempt at a Solution Sure since f=ma A) would have force of 0, since there is no acceleration B) force would be 800N C) force of 0N D)...

Hello there :) First I'm sorry for my English it might be kinda bad ! I Have a little question about Weight and Pressure, Hope this is the right place. Here in this image we have 3 samples, A, B and C. They are 3 different types of shapes fulled with a liquid (let's say water) Talking...

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...

Hi, I'm interresting about the weight of the support of the pendulum with an initial speed. It is the http://en.wikipedia.org/wiki/Pendulum but with an initial speed. The mass come at top with straight initial speed and after turn around the pendulum. I attempt to have the weight of the...

I'm designing a bucket pump for a water well I'll be attaching a pumpjack to. I'm just a regular shop guy so I was kind of stumped on a question of how much upward pressure will be required to move the water up the drop pipe. If the pump cylinder is the same diameter of the drop pipe I figure...

Homework Statement A person who normally weighs 200 lbs is standing on a scale inside of an elevator. The elevator is moving downwards at a constant speed of 7.0 m/s and then begins to slow down at a rate of 4.9 m/s^2. Before the elevator begins to decelerate, the reading of the scale is...

I don't understand conceptually how something accelerating down weighs less. For example, the elevator example of course if you have something with a string and a weight and the acceleration of the elevator increases upward as positive, you get T - mg - ma = 0 and for acceleration down, you...

I need to calculate a lions mass and all i know is the height and mass!

Dear friend, I am getting confused in this question;what i learned till now is that number of proton+number of neutron=atomic mass. But while searching the net i got this equation atomic mass = mass a x fract a + mass b x fract b. can anyone tell me which is the correct (not approximate)...

The weight of a body is less when it is submerged in water, due to the upthrust. But the weight of the water column above the body can be far more than the upthrust(weight of the displaced water). So is it not that the weight of a body can increase when it is submerged in water?

Hey, Imagine a frictionless inclined plane situation where the ramp goes up and to the right. If we put an object on it with any mass m, would it be fair to say that both of the components of the weight are negative? My reasoning is that the x component causes acceleration to the left and the...

i can't figure out how to calculate this. Please help! How many grams of 6.000 wt% aqueous HF are required to provide a 50% excess to react with 10.0 mL of 0.0236 M Th4+ by the following reaction? Th(4+) + 4F - → ThF4 (s) I found the molarity for Th(4+) to be 2.36*10^-4.. I'm not really...

I was wondering, in my class we have been dealing with a lot of equations related to some weight attached to a spring which is attached to a fixed point and has some force being applied to it or something like that. Where exactly is such a thing encountered in real life?

An oblong weight of uniform shape and density is supported horizontally on two supports. The placement of the two supports can be shifted. What is the best way to determine what percentage of the weight is born by each support given any possible arrangement of the supports?

Hi! I am trying to build a stand with a boom arm for my acting classes and I need to find the weight required to balance it. The problem is that it looks like I was more like a swan when I was swimming in the physics lessons ... no a lot of drops stayed on my plumage ... :) Help...

Homework Statement A fisherman in a boat is using a "10- test" fishing line. This means that the line can exert a force of 45 without breaking (1lb = 4.45N). If he accelerates the fish upward at 1.8m/s/s , what maximum weight fish can he land, in Newtons? Homework Equations F=ma The...

Hey all, Just a quick overview of myself, I have recently started rock climbing (6 month) and I'm finding myself becoming more curious about the technical equipment involved. I'm finding it hard to word the questions I'm trying to find the answers too. So I'm going to try and I'm...

I have something I need cleared up and looking for some calculation help. I know that water changes density with temperature but does it change due to lack of gravity when the moon is close? So to clear things up I guess I need to know what and how thoes changes will affect the weight of water...

I'm using the app on my iPod that's for myfitnesspal. Great app to help count calories. Also, I'm doing the Zumba exercise program to help with the weight loss/tone up. Any opinions on all of this??

Homework Statement Two body move apart by force. Frictional forces are considering. How to calculate the ratio of weight? m1<m2 Ft1=k*g*m1 Ft2=k*g*m2 Homework Equations v1(t1)=\frac{F_{t1}-F}{m_{1}}*t_{1} x1(t1)=\frac{F_{t1}-F}{m_{1}}*\frac{t^{2}_{1}}{2}...

Homework Statement As you ride on a ferris wheel, your apparent weight is different at the top and bottom. Calculate your apparent weight at the top and bottom of a Ferris wheel, given that the radius of the wheel is 7.2 meters, it completes one revolution every 28 seconds, and your mass is...

Hey, About Newton's Second Law. To compute our weight on Earth using standard g, we use F=ma replacing F and a with W and g (or -g), respectively. So then from this, I gather that weight is a consequence of gravitational acceleration (and mass). So then, it is appropriate to say that our...

Homework Statement This is a "DOE" (Design of Experiment) problem. Basically, the construction is fairly simple. 3 pulleys, 2 on either side, and a free pulley with a weight suspended on it in the middle. Picture is available (don't mind my crappy paint skills, rope lengths are all...

Hello, Thank you all for the help here. Here we go, I have a known solid weight start of the propellent. I know the PSI of a known volume chamber(After combustion) and Temperature, can I find density? So example Bullseye powder has a load of 0.336954332 grams (5.2 grains) The volume...

Since it has a decimal it would be 20kg * 9.8m/s which equals 196kg m/s^2 = 196N But the decimal means i have to round two sig figs, which would make it 200N? A very simple problem, I really don't know why I'm asking it.

What weight does our weighing machine show?Is it the mass or weight(mg)?

Can a man whose weight is 50KG (but powerful arms) lift another man with 70 KG weight using an overhead pulley. I guess no since the light man is not clamped to the groud, his arm strength will not bear any significance and he can lift only the wieght(on other side of the pulley) equal to his...

Homework Statement What is the weight percent concentration of a saline solution prepared by dissolving 2.440 mole of KCl in 10 L of water? Homework Equations The Attempt at a Solution

This is more of a conceptional question. Let's say you have 1L of water in a bucket on a weighing scale, which currently reads 50N. If a couple of ice cubes were added, would the weighing scale read 50N + weight of 2 ice cubes? Side-Notes: density of the ice < density of water ice...

Homework Statement The weight of a baby measured over an 11-month period is given in the weight chart below for this problem. Weight (lb) Age (months) 6.6 0 (birth) 7.4 1.0 9.6 2.0 11.2 3.0 12.0 4.0 13.6 5.0...

Anyone who knows how to calculate the time a formel car will take from 0-75meter. The specs are 110HP and weight is 300kg. I've tried to calculate this without any luck..

I have my own theory on this, but first would like to ask the forum. And the members answering on my other thread, this question is separate but needs to be answered first. Also I have started answering that one. If use lift 80% of your 1RM, repetition maximum, why is it easier on a barbell...

Hi I just wanted to know what is the mass (in kilogram) of an average car and the mass of an average engine. This is for my project and I want to know their masses to make a scaled model of a car for my experiment.

Does your weight change in elevator? I have recently found an answer to this question but I can't understand it completely. So, here is the answer : No, your weight is unchanged. To provide the acceleration upwards, the floor or scale must exert on your feet an upward force that is greater in...

Increase in weight if an object is illuminated Are there experiments which show that the weight of a body, with initial mass between 1 g and 1 kg, really increases if illuminated for a certain time? Photons have energy E = hf but no mass. If the weight of a body gets bigger after being...

Air rises in water at about one foot per second of time. If a container of air has a lifting force of 100 Lbs and rises at one foot per second what happens when a 10 lb weight is attached to it? What is its speed in the water then? What about 50 Lbs? or 90 Lbs? What is the speed reduction to...

Hi..all. I have replaced a connecting rod against a failed one (in a 10 piston Benz engine) which is 100 GM lesser than original one since the supplier has modified to Euro norms and old rod no more availble. Now after woking 100 odd hours, the engine failed. After dismantling the engine it was...

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)...

Homework Statement Suppose the vertical loop has a radius of 6.81 m. What is the apparent weight (Wap) of a rider on the roller coaster at the bottom of the loop? (Assume that friction between roller coaster and rails can be neglected. Give your answer in terms of m and g.) R = 6.81 m...

Hi, I am looking for a 115 VAC motor (able to be plugged into an ordinary power outlet) that is capable of raising and lowering a load of up to 150 lbs. (attached to a cable and a pulley) at the speed of 6 inches per second. I want the speed to remain constant even if the load changes. How can I...

Homework Statement A glass ball of radius 2 cm sits at the bottom of a container of milk that has a density of 1.03 g/cm^3. THe normal force on the ball from the container's lower surface has a magnitude of 9.48 * 10^-2 N. What is the mass of the ball? Homework Equations Normal force +...

It may superficially sound like a stupid question with a simple answer, but let me explain in more depth. Calories are units of energy, as you probably know, and grams are the the weight of the food. So calories are not directly related to the weight of a food. Foods range in the amount of...

Homework Statement A uniform 165 N bar is supported horizontally by two identical wires A and B. A small 185 N cube of lead is placed 3/4 of the way from A to B. The wires are each o.75 m long and have a mass of 5.50 g. If both of them are simultaneously plucked at the center, what is the...

1. Suppose Earth is a perfect sphere of radius 6,370km. If a person weighs exactly 600N at the north pole, how much will the person weigh at the equator? Givens: r = 6,370km = 6,370,000m Weight at north pole = mg = 600N Homework Equations ω_{av} = θ/t ƩF_{net} = ma a_{c} =...