Fall Definition and 903 Threads

Homework Statement a hot air balloon is ascending at the rate of 10 m/s and is 61 m above the ground when a package is dropped over the side. with what speed does it hit the ground Homework Equations y(final) - y(initial)= vt + .5at^2 v(final)=v(initial) + at a= -g = 9.8 m/s...

Homework Statement A bolt comes loose from underneath an elevator that is moving upward at a constant speed of 6.0 m/s. The bolt reaches the bottom of the elevator shaft in 3.0 s. a.) How high above the bottom of the shaft was the elevator when the bolt came loose? b.) What is the...

Another free fall topic :) Here I don't really know where to start Homework Statement A body in free fall covers 64% of the total distance fallen in the last second. From what height did it fall? Homework Equations y= y1 + y2, where y1=0,36y and y2=0,64y y=.5at², where a=g=9.8...

1. A ball is thrown vertically upward with an initial speed of 10m/s from thetop of a building, at a height of 25m from the ground. Assume free fall conditions. a. To what maximum height above the ground does the ball rise? b. With what velocity does the ball strike the ground? c. How long...

Design, fabricate and test a device that will autonomously provide signals (visual, audio and/or others, creativity appreciated) as close as possible to two times following initiation. One signal shall be after 30 seconds. The second signal shall be at a time between 13 and 24 seconds, the...

So i just transferred to university and I am taking thermo, physics 3, a lib ed and was thinkin about takin this applied Fourier analysis course. I am just wondering if it sounds like a good idea or should i wait for a few semesters to take it so i'll actually be using it in my classes. Thanks

I read about this stuff a few years ago, and it seems that nobody gives too much attention to it. Its about an experiment with "cold" neutrons in free fall, and here is the original publication (2004) found on Institut Laue-Langevin's website...

Homework Statement A stone is thrown vertically into the air from a tower 110 ft. high at the same time that a second stone is thrown upward from the ground. The initial velocity of the first stone is 60 ft/s and that of the second stone 85 ft/s. When and where will the stones be at the same...

A 10 kg mass is in free fall with no air resistance. In order to slow the mass at a rate equal to the magnitude of g, an upward force must be applied with magnitude: F=ma F=(10kg)(9.81m/s2) = approximately 100N So in order to slow the mass at a rate equal to g it should be a...

Can you help me with this please, an approach on how to proced would be great. Homework Statement From top of a tower two bodies are dropped with the same velocity Vo and same inclinations \alpha1 \alpha2. both bodies fall in the same point of the ground. Calculate the hight of the tower...

Registered my classes for the upcoming Fall 2010 semester; these classes are only courses I need in order to transfer to USF. I've already completed all other requirements except Chem I + Lab. Registered courses: (17 credit hours total) Calculus III - M/T/W/TH Physics II + Lab - T/TH...

I'm going to be a freshman in chemical engineering this fall. I'm not supposed to take physics until the spring semester, since we take it with Calc II. However, I technically can place out of calc I from my AP score. I'm not going to do this, because I don't feel that I have a strong enough...

Hi PF members, I've been thinking about taking Modern Algebra I and Real Analysis I in the same semester, but I'm having doubts if this is a realistic schedule. A semester is only four and a half months long and I don't believe that I can fully comprehend the subjects I'm studying for that...

I have this question on my Circular motion assignment, but its somehow connected to free fall. I'm unable to picturize the situation mentioned in question... A 3.35 kg block is attached to a string that is wrapped around a 1.22 kg, 5.03 cm diameter hollow cylinder that is free to rotate on an...

Homework Statement A rock climber stands on top of a 50-m-high cliff overhanging a pool of water. He throws two stones vertically downward 1.0 s apart and observes they cause a single splash. The initial speed of the first stone was 2.0 m/s. a) How long after the release of the first stone...

THIS IS NOT A HOME WORK QUESTION THIS AS FROM ANOTHER Tutorial find the electric field E need to prevent an electron from falling down to ground, when close to surface of the earth. i approached this question saying that take gravity into account and take Earth to be negatively charged...

Hi all, does anyone happen to know when the Fall 2010 physics GRE is? I tried to register for it, but ETS's website said "Registration closed for 2010 year". I thought there was a Fall offering of the Physics GRE, typically? Does anyone know about that? I have to plan my study time for this...

Observer is falling into the BH. He looks at the stars. What does he see as he approaches EH? Universe in fast forward? Supernovas blasting at increasing rate, his galaxy merging with others... At the very moment he crosses EH (he is still alive somehow) his last observation would be that...

1. A rock is dropped from rest from a height above a strange planet, and a strobe-light photograph is taken. The image is damaged in transmission to Earth so that an unknown part of the top of the picture is lost. However, five successive images of the falling rock can be seen. The spacing...

Here are the tabulated t = time (sec), v = velocity (m/s) = g(t), and d = displacement (m)=4.9(t)^2 for an object if dropped (free fall) from rest position. When t=0, v=0, d=0 When t=1, v=9.8, d=4.9 When t=2, v=19.6, d= 19.6 When t=3, v=29.4, d= 44.1 When t= 4, v=39.2, d=78.4 When...

I am a sophomore Mechanical Engineering major transferring from a really crappy college to the University at Buffalo, which is a halfway decent engineering school. I want to rock my first semester with a 4.0 and try to get some scholarships for my junior year. The problem is, that I need to...

Two objects of different mass should fall at the same time, both with acceleration g. That is if the objects are in a vacuum, have the same initial speed and height. However, considering air resistance, the acceleration diminishes until both the drag and the weight are equal. Now, a canon ball...

I've been trying to derive the full solution to the problem of free fall when the distances considered are large (and hence, the acceleration is no constant, but a function of height). This isn't homework, I was just curious. The problem is innocently simple, but yields a differential equation...

I'm having no end of trouble with this seemingly simple problem: Homework Statement What's the minimum mass of a black hole for which you could survive a fall through the event horizon without being ripped to shreds? Why would you be ripped to shreds for smaller black holes? Homework...

Here's the deal...I had a really bad precalc teacher in high school. She had a baby a week into the course and we had a generic watch-movies, do crossword puzzles sub for the rest of the year. The class made me unmotivated for math, so I didn't try to learn anything on my own. This year...

Homework Statement To find the height of an overhead power line, you throw a ball straight upward. The ball passes the line on the way up after 0.85 s, and passes it again on the way down 1.2 s after it was tossed. (a) What is the height of the power line? (b) What is the initial speed...

Homework Statement While riding on an elevator descending with a constant speed of 3.3 m/s, you accidentally drop a book from under your arm. (a) How long does it take for the book to reach the elevator floor, 1.0 m below your arm? (b) What is the book's speed relative to you when it...

Homework Statement I am having a heck of a time trying to solve these problems. Please help if you can. A hot air balloon has just lifted off and is rising at the constant rate of 2.4 m/s. Suddenly, one of the passengers realizes she has left her camera on the ground. A friend picks it up...

Homework Statement An object is in free fall at the surface of the Earth. In a certain 1.0 second time interval, the average velocity of the object is measured to be 2.0 m/s downward. What was the velocity of the object at the beginning of the 1.0 second interval? Homework Equations...

I get that gravity is acceleration we feel as a result of moving through spacetime. But I don't understand why it is that, when you fall, you are closer to not accelerating than when you sit still. Can someone please explain that? thanks!

I am a computer science major with a minor in mathematical sciences. I just finished up Calculus I this semester (with a 97%, yay!) and scheduled to take Calculus II this summer. The list of available fall classes was just released and I'd like to take either Calculus III or Linear Algbera. I...

Hi, guys. This is my schedule for the coming up fall. Appl Differential Equations I Intro to Number Theory Foundations of Math Advanced Calculus I I know it will be challenging. Do you think I should take all these classes at once or should I drop the Advanced Calculus I? Any thoughts...

Hi, If you no the height of an object only, assuming no frictional forces, and that it is on earh. Can you determine how long it will take to hit the ground? Thanks James

Apologies if this is a little early. I don't know what other universities are doing, but mine just opened up Fall 2010 registration to the masses (Honors college could do it earlier). Anyway, here's mine: Modern Physics Intermediate Lab Physics Mechanics (the upper-division version)...

Homework Statement Two 54kg blocks are held 30cm above a table. As shown in the figure, one of them is just touching a 30cm long spring. The blocks are released at the same time. The block on the left hits the table at exactly the same instant as the block on the right first comes to an...

Homework Statement Atwood’s fall machine consists of two weight of mass m1 and m2 attached with a massless rope running around a spinning wheel of mass M and radius R without slipping. The spinning wheel is attached at its center and rotates around an axis through its center without friction...

A friend of mine ask me what field of science Fly-by-wire control systems of aircraft/space craft falls under. I really didn't know this my self so it made me curious. He also said something about the computers in cars, and GPS. What are they under, computer science, engineering?

I'm in my second year of EE at my university right now, and I'm going to have to pick what I want to specialize in. That means I should now have some sort of idea of what I actually want to do once I graduate. The class that I've enjoyed the most thus far has got to be one called Digital...

Homework Statement A tennis ball is hit down at an angle of 30° below the horizontal from a height of 2 m. It is initially traveling at 5.0 m s−1. What is the velocity of the ball when it hits the ground if we can neglect air resistance?Homework Equations The Attempt at a Solution ok so I...

Homework Statement An astronaut on a strange planet finds that she can jump a maximum horizontal distance of 15 m if her initial speed is 3 m/s. What is the free fall acceleration on the planet? Homework Equations R=Vi^2sin2α/g The Attempt at a Solution 15=9sin2α/g g=9sin2α/15

Hi all, Since the pre-registration time for the Fall semester is approaching i need to make plans as what to take next semester. Specifically, i am planning on taking one or two reading courses since they are not offered via regular curriculum. While it is not for sure that i might be...

Homework Statement Describe the motion of a light bulb falling from the ceiling of a train with a constant acceleration. The train's motion is horizontal with respect to the ground. Describe the motion of the light bulb if you are at rest on the rails. If you are at rest on the train. If...

I'm looking ahead at my fall schedule. I work roughly 20 hours/week, but it looks like that will be cut back to around 12 hours/week. I'm definitely taking Modern Physics II (undergrad QM) and Intermediate Mechanics. I'm considering taking Intro. to PDE with this professor, but honestly I'm a...

Homework Statement 71. A paratrooper fell 370 m after jumping from an aircraft without his parachute opening. He landed in a snowbank, creating a crater 1.1 m deep. Assuming the paratrooper's mass was 80 kg and his terminal velocity was 30 m/s, estimate : a) the work done by the snow in...

I have an MS in physics and did not get into any of the phd programs I applied to. What schools are still accepting applications, and which ones might still have funding for students? I am interested in many areas of physics and my experience is in computation and some nuclear. I have average...

Hello, first post. I hope that someone can help me with this. I will roughly summarize the problem, and what I've done thus far. Homework Statement A lady was in an elevator that free-fell 6 feet and abruptly came to a halt. We had to determine a reasonable best case and a reasonable worst...

I have been employed at the same distributor for about 4 years now and just got word last week we have been bought out. Right after the first of the year our owner announced he was retiring and then almost immediately the due diligence began. We have now went from a small company comprised of...

Suppose a 136 kg manhole cover is launched 50 feet in the air. What is the speed of the manhole cover when it hits the ground on its descent, in m/s and mph? I converted 50 feet to 15.24 meters, but I do not know what equation to use here. I understand that acceleration due to gravity is...

Figure 2-42 shows a simple device for measuring your reaction time. It consists of a cardboard strip marked with a scale and two large dots. A friend holds the strip vertically, with thumb and forefinger at the dot on the right in Figure 2-42. You then position your thumb and forefinger at the...

Free fall problem, Help!? Homework Statement Hi, I am having trouble figuring out this problem: A ball is thrown directly upward with an initial velocity of 10 m/s. If the ball starts at an initial height of 2.3 m, how long is the ball in the air? Ignore air drag. Homework Equations...