Fall Definition and 921 Threads

Homework Statement (Yes this is a question about Batman.) To escape from Batman, 4 villains on motorcycles drive horizontally off the edge of a parking garage, landing in a pile of sand. The riders all have different initial speeds: v0A = 14m/s, v0B = 24m/s, v0C = 18m/s, and v0D = 19m/s...

This isn't so much a H/W question, but we have 2 sets of values, TMax and Tmin. Δ is the difference between them. We are told to get Δ/2 and get the %uncertainty of this. Why do we halve Δ?

when we tie a stone to a string and spin it,it does not seem to fall.why does it happen?i mean to say that,no matter how great its horizontal velocity and centripetal force is,the vertical component of the acceleration won't be affected.it means that the stone should keep falling no matter how...

Homework Statement A package is dropped at time t = 0 from a helicopter that is ascending steadily at a speed vi. What is the speed of the package in terms of V_{i}, g, and t? Homework Equations V (t) = V_{o} + -9.8 t The Attempt at a Solution I thought it was the same as the...

Homework Statement An arrow is fired upward with an initial speed of 38 m/s. What is it's maximum height? How long does it take to return to the ground? How high is it at 1.3 seconds? How high at 3.8 seconds? Homework Equations x = Vo*t + .5*a*t^2 y = .5gt^2 etc. The Attempt at a...

Homework Statement A certain object is falling in free fall down a building. The object falls the last 30 meters in 1.5 seconds. What was the total height it was dropped at. Homework Equations s=(1/2)(g)t^2 The Attempt at a Solution I've tried setting the total height to x+30...

Homework Statement A ball is dropped from the top of a cliff. If time taken for half of the descent is 3s, then what is the time taken for the rest of rest of the descent? Take g=10m/s2 Homework Equations T=√(2h/g) v=u-gt s=ut-gt2/2 The Attempt at a Solution T=√(2h/g) h=T2g/2=45m...

Hi, As I understand, the distance covered by an object in free fall is described as d = \frac{1}{2}gt2 or d = 5t2 on earth. Objects accelerate at 10 m/s2. Using the first equation, if an object has fallen for 5 seconds then it has covered a distance of 125 meters. If objects, however...

Hi, In a demonstration that was shown in class, two paper cups were dropped from different heights. The first was dropped from two meters and the other was dropped from one meter. Both landed on the ground at the same time. Why is this so? Would it be reasonable to say that if I dropped one...

So here is the scenario: an adult male 80kg, 6ft tall, slim build free falls into the open ocean feet first, hands locked into the groin. Speed at entry can be 200km/hr. We can assume the water is perfectly stile in reference to the surface tension. and for the body we can estimate some factors...

Hey everyone, I'm not sure if there is an effective answer to my problem, but here goes: I am working on Ramachandran plots for short peptides (3 amino acids long). For every snapshot of the protein (this would be my data point) there are two angles being recorded, the phi and psi angles...

Does space have some kind of buoyancy that prevents stuff from falling down? for instance, why doesn't the Sun fall downward eternally? Like, it is clear why the moon doesn't fall out of the sky but what is holding the Sun up in space? If you say the galaxy what is holding it up? what is the...

Hi people! I have a real life problem that i can't solve...Im trying to figure out the tangencial speed or angular velocity of a hatch at the moment it is about to close (initially it was closed). The hatch has been accelerating due to gravity. It looks much as a pendulum to me. But, it gets...

With this coming semester I have some interesting options for my schedule. The following 3 classes can be interchanged within my schedule: Data Structures - Studies data abstractions (e.g., stacks, queues, lists, trees) and their representation techniques (e.g., linking, arrays). Introduces...

An object is thrown vertically up from the top of a tower with an initial velocity of 29.4m/s. Four seconds later another object is drop from the top of the tower. How many seconds will the two be at the same level? I'm trying to solve it for a day already. Sorry, I suck at this :P

Homework Statement Falls result in hip fractures are a major cause of injury and even death to the elderly. Typically, the hip's speed at impact is about 2.0 m/s. If this can be reduced to 1.3 m/s or less, the hip will usually not fracture. One way to do this is by wearing elastic hip pads. If...

in free fall without air resistance what is the force that causes the constant acc? Is it the object weight ? And in free fall with air resistance what is the applied force ? Is it the weight of the object and the resistive force is the air resistance? And the net force is the one that causes...

Hello. For free fall to occur, does the rate at which you fall have to equal the gravitational field strength at that point above the surface? If I'm in an airplane and accelerate towards the ground at an acceleration of 9.8ms^-2 equal to that of the Earth's gravitational field, then I...

And if we knew everything about the pen and the surface on which its placed, could we predict the direction in which it would fall? Could you then somehow put the pen so that it won't fall over? It doesn't have to be a pen by the way, could be a pencil or similar things that tend not to...

I've been searching around this forum and the internet, and I still have a hard time understanding how curved spacetime, as described by General Relativity, can cause us and objects to fall back on the surface of the Earth. I get the concept of Geodesics and how planets revolve in orbit around...

Consider two stationary blocks of same mass suspended by a massless string over some kind of pulley. The net force on both of them is clearly 0. Now suppose we somehow gave on of them a downwards velocity by some kind of energy transfer. Then intuitively the block would start to fall down. But...

My mom got some and I'm wondering if it's safe to use. Is it actually effective? And are there any other issues associated with it?

So there is this girl I like. I want to make her love me. Can anyone teach me how to?

I am a senior physics major and I have several electives (up to 2) to fill with math courses this Fall. I have previously taken: Calculus 1-3 (Stewart) Ordinary Differential Equations (Edwards and Penny) Partial Differential Equations (Haberman) Matrix Algebra Parallel Processing I am...

The equation for the fall velocity (terminal velocity) of a particle of a material in a viscous medium has been derived from theory as: Vt = gd^2(Pp - Pm) / 18 u Where: Vt is the terminal velocity in m/s; g is the acceleration due to gravity; d is particle diameter in m; Pp and Pm are the...

Homework Statement When a box falls in a vacuum, it accelerates at 10m/s^2 and if the mass is 10kg, then it has a net forfeit of 100N. As it falls for 10s, it has a final speed of 100m/s. At the moment of impact, there is a reaction force of 100N acted upon the box by the earth. But since the...

Say I have a cuboid box (eg 120 * 60 * 10cm (lbh)). Is there a way I can add non-uniform mass to it to force the center of gravity on a preferred point (eg making one half heavier than other) - and then when I drop it horizontally or vertically, it always touches the ground at same side (but may...

1-D Kinematics Problem/Free Fall. "A helicopter carrying Dr. Evil..." NOTE: I'm new here and I wanted to make sure I am not breaking the rules: I show most of my work step by step for this problem since there are so many things going on in it. My question is whether or not my though process is...

So far I've been studying chemical engineering and it is mostly applicable. I'm not sure which classes I should be taking, though, and whether ChemE is even the best program to study within. Ideas?

A small steel ball is hot vertically upward from vertically upward from the top of a building 25 above the ground with an initial velocity of 18 m/s . 1 ) In what time it will reach the ground ? 2 ) compute the velocity with which it will strike the ground and the total time it is in the...

I know that light can, because otherwise black holes wouldn't exist. But can sound fall? And are there any effects caused by this. By doing a rough calculation, if sound could fall, sound would have a maximum vertical range of about 5km. Do we see this in real life?

I was hoping someone could clear this up for me. I've been thinking about it a bit, and I am thoroughly confused. Here is what I have come up with so far. The situation: A horizontal (wheel vertical) gyroscope spinning counter clockwise held up at one end by a string. Now change views so...

I have almost no formal training in physics, and I am only a junior in high school, so this may be a stupid question. But, anyways, I recently watched some documentaries on gravity and general/special relativity. I understand why objects orbit in accordance with GR (the orbiting object is...

in elevator before cable break mg=kx in frame of elevator after cable break F(gravity)+F(pseudo)+F(spring)=0 answering question is not tough but i am interested in other things that will happen with this system. Will the elevator move with a constant acceleration with respect to a...

Homework Statement A small piece of Styrofoam packing material is dropped from a height of 2.00 m above the ground. Until it reaches terminal speed, the magnitude of its acceleration is given by a = -g + bv. After falling 0.500 m, the Styrofoam effectively reaches terminal speed, and then...

I will be attending a university in the US for aerospace engineering this fall as I stated above and I understand the level of difficulty that comes with this major but I just wanted to know if anyone had any advice for me, I know that’s a broad question to ask. My plan is to go into...

Lets say I am in free-fall towards some massive body and I have 2 mirrors and photons bouncing in between them. Now as I fall closer to the massive body the light should get blue-shifted right? And let's say that the frequency of light that I started with is x. As I fall closer I put a jar of...

It's on page 4 (this isn't homework, just something I stumbled upon, it's also in Griffith's 8.17):http://www.physics.udel.edu/~msafrono/425/Lecture%2018.pdf . Can someone help me understand this solution? What exactly is happening...are there particles at h/2 that are smashing against the...

Hey guys, i am a sophomore (about to be a junior in 1 month), in college majoring in Biomedical engineering and i am planning to take Organic chemistry, multivariable calculus, physics 2 and the labs. Do you think this is too much, my only concern is with organic chemistry. I originally took it...

Why Don't Planets "Fall" into the Sun? Ok, guys, I am new to physics (just studying it on my own before taking it next year in school) and watched a bunch of videos online about general relativity and gravity. I'm sort of stuck, though, with why if general relativity explains gravity as...

hello every body. I have a high school problem a straight horizontal wire is falling freely in a homogeneous horizontal magnetic field, perpendicular to the wire and i want to find the inductive voltage. I said E= Blv=Blgt But I can also say E=ΔΦ/Δt=BΔΑ/Δt=Βl1/2gt [t][2]/Δt=1/2Blgt why...

I am a rising senior Physics Major who needs one more class to meet the credit hour requirement to keep my scholarship. These are the class that fit into my schedule that my adviser told me to look at: Intro to Software Engineering - really just advanced C++, UML use, memory management, and...

we are in weightless condition because there are no resultant force between Earth and me,at this instant, Earth and me are in the opposite direction moving toward each other,will Earth oso can consider weightless? when i free falling p/s : beg pardon at 1st typing massless ,typing error ==

Roughly, when is the latest I could take the GRE for fall grad school admission? I'm a second semester junior currently, and I am planning on going straight to grad school after senior year. Would taking the GRE (applied physics major) in the fall (around September) be too late? Also...

In the classical view of the electron, would the electron "fall" into the nucleus? I'm not asking why the electron doesn't fall into the nucleus. I know this is explained by quantum mechanics. But in class the other day, my professor said that treating the electron as a classical particle...

Hi, An object is falling near the surface of the Earth. We assume there is a drag force acting on it due to the air molecules. It's initial conditions are such that it rotates and is in a chaotic motion. Will the object will fall in the end in such a way to minimize air drag? And if yes -...

When I was in high school I loved science, NASA and outer space stuff. For some reason even though I loved science, I never really applied or pushed myself academically. When I finished high school I started taking classes at my local community college. I only took a few classes at a time and...

Right now I am taking conceptual physics which is the most basic physics class my college offers. I am taking Calculus 1 right now and plan to take calculus 2 in the summer (2 month course). So do you think calc 1 and 2 will be enough to be prepared for mech physics? Or do you think i...

Box on a sphere is nudged-- when does it fall off? Homework Statement A box of mass "m" is placed on a sphere of radius "r". The box is given an extremely small nudge to get it moving. (a) What is the maximum speed the ball may have without leaving the sphere? (b) At what angle from the...

Homework Statement The flag pole is 10m tall. The base of the pole has rusted and the pole topples over. What is the time taken for the pole to hit the ground? s = distance = 10m u = initial velocity = 0 m/s v = final velocity = unknown a = g = acceleration due to gravity = 9.81 m/s2...