Fall Definition and 921 Threads

Homework Statement Two stones are thrown simultaneously, one straight upward from the base of a cliff and the other straight downward from the top of the cliff. The height of the cliff is 6.00m. The stones are thrown with the same speed of 9.00 m/s. Find the location (above the base of the...

Homework Statement A test of the prototype of a new automobile shows that the minimum distance for a con- trolled stop from 100 km/h to zero is 41 m. Find the acceleration, assuming it to be constant as a fraction of the free-fall accel- eration. The acceleration due to gravity is 9.81...

Homework Statement During the second world war the Russians, lacking sufficient parachutes for airborne operations, occasionally dropped soldiers inside bales of hay onto snow. The human body can survive an average pressure on impact of 30 lb/in2. Suppose that the lead plane plane drops a...

Hi, This is from "3000 solved problems in physics". Yes, I have the solution but I still have a question. a ball is thrown vertically upward with a velocity of 20 m/s from a top of a tower having height of 50m. On its return it misses the tower and finally hits the ground. What time t elapses...

when a meteor hits a satellite what will happen to its motion

Hi all, I have a GR exam on tuesday and getting a bit confused as to how to find the metric for an observer in free fall a distance two schwarzchild radii from a black hole. I know this is a bit of a basic question but I am just wondering if I am correct to substitute r=2rs and dt=d(tau)...

I am trying to figure out whether or not an employee of a University or Community college would technically be working for the Department of Education? The reason I ask is that I have a juvenile criminal charge that is sealed. I can deny the charge ever took place except when applying for...

What do they expect transfer students to do?! I'm transferring as a junior and need engineering classes but they are basically all filled up. I can't register until orientation and I'm signed up for the first one which is in early July.

I was told i have till wednesday to do a project on physics I've never done before in class, this being a regular high school physics class. So i decided to figure out how a parachute affects free fall and the calculations and stuff to show this. So far I've found an Air Resistance formula...

I come from Quebec, which means I had to go to Cegep (it's a post-secondary school required to attend Universities). There's 2 main "branches" to go to electrical engineering at uni here: 1) Complete a "general sciences" 2 years course at Cegep, which is what I did. It's the normal path to...

Homework Statement When the ball dropped from a height of 2.5 m on the floor, it bounces back to 1.4 m in height. Air resistance is taken into account. g= 9.81 m/s2 Homework Equations a) the speed at which the ball hits the floor? b) How much of the energy consumed in collision with a...

Help! Free fall, looking for time of motion off of a bridge. Homework Statement A person standing on a bridge throws a ball upward with an initial velocity of 23 m/s straight upwards so if it comes back down it will just pass the edge of the bridge and keep going down. a) where will the ball...

This is not a homework question but could not find a better place to post it. Why doesn't a spinning top fall over instantly? Also why does it fall later? What makes spinning so special? Are the answers different for top spinning with its axis fixed and the top with its axis moving conically...

I have recently been studying GR to find out if you really can find out how fast an apple will fall on the surface of the Earth in GR. Its simple with Newtonian mechanics, just use F = GMM / R^2 A = GM / R^2 I started to with the geodesic equation. Which Christoffel symbols should I...

Homework Statement On September 8, 2004, the Genesis spacecraft crashed in the Utah desert because its parachute did not open. The 210-kg capsule hit the ground at 311 km/h and penetrated the soil to a depth of 81.0cm . Assuming it to be constant, what was its acceleration (in m/s2 )...

Put a one rupee coin over a piece of card paper placed on an empty glass push the card with a sudden stroke of finger card will move ahead while the stone fall in glass, Why?

I was just watching a program on tv about gravity. The showed one example of a tube through the Earth from one point on the Earth to another point on the Earth's surface. This shows how we would accelerate relative to the Earth until we reached the centre, and then decelerate until we get...

Why doesn't dark matter fall into black holes ? Assuming it doesn't of course. If it did then surely huge amounts would have fallen into black holes. By now they'd be full of the stuff & more massive than they are. So I'm assuming for some reason dark matter doesn't fall into black holes. In...

1. Calculate the percent difference of freefall acceleration for the light and heavier picket fence Lighter Picket Fence - Mass 95.84 g | Acceleration 6.4141 m/s2 Heavier Picket Fence - Mass 128.16 g | 8.995 m/s2 2. Compare each of the values from the graphs to the accepted value of free...

Homework Statement True or false: a two input nor gate is designed to have the same worst case rise and fall times. The best case fall time is smaller than the best case rise time in this gate. Homework Equations - The Attempt at a Solution The second part i get, the best case fall...

as far as i know angular mechanics contains no axioms in it. it just a helpful tool to solve problems with a rotating body, but technically if you regard the body as a set of independent particles you should be able to solve any problem without angular momentum, right? so how can you show a...

While riding on an elevator descending with a constant speed of 3.0 m/s, you accidentally drop a book from under your arm. How long does it take for the book to reach the elevator floor, 1.2 m below your arm? What is the book’s speed when it hits the elevator floor?My question is why is 3.0 m/s...

Homework Statement A crate is hanging from a cable as shown in the diagram. A monkey that is inside the crate, sits on a ledge that is 1.225m above the bottom of the crate. The monkey steps off the ledge and when he hits the bottom of the ledge, it takes .125 s to stop. The tension in the...

Does dark matter fall into a black hole, and create radiation as it falls in like normal matter? If not, why not? If so, can we use this to detect it directly?

Homework Statement The rise and fall of water in a harbour is simple harmonic. The depth of water varies between 5.0 m at low tide and 9.0 m at high tide. The time between sucessive low tides is 12 hours. A ship, which requires a minimum depth of 6.0 m approaches the harbour at low tide, how...

Homework Statement A ball falls from the top of a building. It falls past a window. It is in view for .16 seconds. The window is 1.7 m long. How high was the building off which it was dropped? Homework Equations I'm trying to use .5 a t^2 + vt + x but it's not working The...

will a 2m(rest length) car moving near lightspeed fall in a 1m hole?

Homework Statement What are the applications of free fall in our daily life? Homework Equations How is it applied?The Attempt at a Solution One example is sky diving,I need to know more. A sky diver must have knowledge on the concept of free fall like what position he/she should be into...

Homework Statement Design a simple Op Amp circuit to find the position as a function of time of a falling body Homework Equations y=y_0+1/2gt^2 Assume y_0 = 0 at t=0 The Attempt at a Solution I used an integrator Op Amp with a triangle wave input. I chose the values of the...

General particle motion in an FRW spacetime is governed by the geodesic equation, \frac{du^\mu}{ds} + \Gamma^\mu{}_{\nu \alpha} u^\nu u^\alpha=0, with u^\mu = \frac{dx^\mu}{ds} and where the Christoffel symbols are given in the notes. Show that the physical momentum of any particle always falls...

Homework Statement The exact problem can be seen in the attached jpeg, and is summarized without figures here: Homework Equations Volumetric flow rate: Q = A*V Continuity equation: (d/dt)*(Integral Of:density*dVolume) + (Integral Of:density*velocity*dA) Velocity of rain fall down the...

Hello, I am new to this site. I am currently active duty military (navy) and I am trying to teach myself physics because when I get the time, I would like to take some college physics classes. I downloaded a few physics books online and I am trying to page through them. I am having some...

x’’(t)=g-Fd/m=(9.81metres/sec^2)-(k/m)(x’(t)) where x''(t)=du/dt and x'(t)=u=dx/dt I enter this at http://www.wolframalpha.com/input/?i= and I get the solution x(t)= -(c1me^(-kt/m))/k+c2+9.81(m/k)t But x(t=0)=0 x’(t=0)=0 x(t=0)=c1+c2 x’(t=0)=c1-c2 =>c1=c2=0 =>x(t)=9.81(m/k)t and this...

Homework Statement . A ball is thrown straight up at t=0. It is found to be falling with a speed of 8 m/s at t= 6 sec. Find the displacement of the ball.Homework Equations The Attempt at a Solution v=v0-gt 8=v0-60 v0=68 deltax =v0t - .5gt2 delta x = (68*6)- 5*36=228 but it says the answer is...

Please refer the attached setup. * The laser source is moving at very high speed (say, V=c/2). * The slit is very close to laser source. * The screen is far away from the laser source. I would like to know, On the 'screen', where the laser beam will fall. A or B? -Jubair

Is there anybody that knows anything about fall factors? I'm a climber trying to learn about the consequences of overloading my gear. Below is a couple of links. One explains what a fall factor is and the other is a calculator that enables you to determine the fall factor and the shock in kilo...

Homework Statement Jane is riding in a hot air balloon that is rising vertically at a constant speed of 3m/s over a lake. She reaches out and drops a rock from the balloon when the distance from the rock to the water is 50m. Use g=10m/s2, and let the up direction be positive. How long...

Homework Statement 2) Problem : You must believe that the coyote is falling at one specific speed at any time during his fall to the ground. Your task here is to find the coyote’s exact speed at each full second of his fall. Once we know this information you can develop a rule that will...

Some introductory line about me apologizing for my ignorance and inability to find answers on interwebs. :smile: If photons get affected by gravitational field (or follow the curvature of space-time created by nearby massive objects) and have in essence some non-rest mass how come they...

Homework Statement For a brief moment, the human body can withstand accelerations of up to 75g. If a sky diver is unlucky enough to have a parachute fail, and hits the ground with a terminal velocity of 50 m/s, what is the minimum distance over which he can come to a rest (assuming constant...

Let's say I was point-like but have mass (not a photon) and I wanted to "go into" a black hole's event horizon, just to see how it was like... :) I am not sure if it would be possible because maybe the black hole would evaporate before I would reach the event horizon, and here's what I'm...

Homework Statement An object falls into free falling from a hight such that during the last second of falling it traverses 1/4 of the total hight.Calculate the time of the fall knowing that there's no initial velocity. Homework Equations I know solve this problem fallowing these steps...

first of all I have a case that is screwed in another case ,I like to know a basic way to calculate the impact force in the screws ,the are 16 screws, I try using the basic impact force formula and the conservation of energy in the free fall,but I am having problems since I don't have the D...

D=Drag Coefficient p=Density of air A=Cross sectional area v=velocity a=acceleration F= force F air=(DpAv^2)/2 F net=mg-F air ma=mg-F Air a=g-(DpAv^2)/2m k=DpA/2m so a=g-kv2 dv/dt=g-kv2 dt=dv/g-kv2 using the online integrator from wolfram we got...

Homework Statement Does the acceleration of free fall take the effect of air resistance into account or is it equal to the acceleration of free fall on Earth if the Earth was in a vacuum? Thanks Homework Equations The Attempt at a Solution

Homework Statement Skydiver #1 from the University Skydiving Club steps out of a plane when it is 1 miles above the ground and 10 seconds later skydiver #2 steps out of a plane (at the same height). They both want to land on the ground at the same time. To make an estimate assume that...

Hello, I wanted to know if air humidtiy is high because of a higher temperature does it fall like rain on me or on the clothes or ground what ever after a drop in temperature? The drop in Temperature also means a drop in humidity where does the water vapor goes, i know about cold places...

If air would be compressed to have equal pressure to that of water would objects which are buoyant in water be buoyant in such compressed air too or would they still fall down due to Earth gravity? Or asking differently, what would have to be the pressure of air (lower, equal or higher than...

Free fall, problem, please help Homework Statement A hoist is lifting a naturalist to the top of a cliff at 2.03 m/s vertically. The naturalist suddenly realizes she has left her pet rock behind. A friend picks it up and tosses it straight upward. If the naturalist is 2.50 m above her friend...

Homework Statement A rock is dropped from a sea cliff, and the sound of it striking the ocean is heard 3.7s later. If the speed of sound is 340m.s how high is cliff? Homework Equations Ttotal=trock+tsound distance=Vsound*tsound ts=340m/s-trock x=x+vt+.5at^2 quadratic equation...