Fall Definition and 921 Threads

Homework Statement A student walks off the top of the CN Tower in Toronto, which has height 553m and falls freely. His initial velocity is zero. The Rocketeer arrives at the scene a time of 4.75 seconds later and dives off the top of the tower to save the student. The Rocketeer leaves the...

Does warm water rise or fall in cold weather? I think it falls Does it have to do with convection??

OK, I'll be applying for a couple of universities in the fall of 2007. Now what's more confusing then anything else and is driving me nuts is all the financial aid stuff. The websites say my deadline is February 1. February 1 of what, 2007 or 2008? If it's Feb 2007, then that's crazy. Since I...

If you are in free fall you would be standing still, with no acceleration right? So in a way you are decelerating(or accelerating in the opposite direction) in 9.8m\s^2, when you are standing on the earth, is that true? Or would you have to look at it otherwise? So free fall cannot be...

I'm having trouble with this problem: So for this problem i used F=ma: 79g-88=79a a=8.6861m/s^2 this is the correct acceleration i believe and to find final velocity i used: Vf^2=Vi^2+2ad where d is displacement Vf^2=2(8.6861)(25) vf=20.85m/s I'm using utexas's webhw service, and the...

when a satalite orbits the Earth my text states that it is constantly falling into the Earth as it moves tangentially -- my question is why doesn't the speed of the object falling into the Earth increase radially since it is acted upon by the force of gravity, a force of gravity would cause an...

Is it because the moon is actually falling in free fall TOWARDS the Earth but it is moving in a circular path the same as the Earth's path??

Let's assume that there are no other forces acting besides the gravitational pull of the earth. If a body started falling from the surface how much time would it take before it reached the center of the earth? It seems like an easy problem, but so far I have had no luck. So far I have only...

The question is "Two identical uniform bricks of length 18 cm are stacked over the edge of a horizontal surface with the maximum overhand possible without falling." |<-- 18 cm -->| +-------------+ | block 1 | +-------------+ +-------------+ | block 2 |...

An airplane propeller is 2.08 m in length (from tip to tip) with mass 117 kg. The propeller is rotating at 2400 rev/min about an axis through its center. Its rotational kinetic energy is 1.33x10^6 J. If it were not rotating, how far would it have to drop in free fall to acquire the same...

One of the discussion questions in a lab I did which was basically a free falling object where the kinetic and potential energies were measured. It asks what is the energy transformation equation for a free fall (1-step transformation). Is it just: Total Energy = Potential gravitational energy...

Years ago I read a book that explored what it means to people to satisfactorily "explain" something. There were 5 different levels of "doneness". I'm looking for that book. In a nutshell, the book explored a lecture hall experiment: - a cylinder was placed on a table at the front of the room...

okay my question is kinda stupid, and i know i totally sux at physics. if a bullet is shot upwards, will it fall at an equal or greater force? i know its decelerating as it is shot up, and it would be acclerating as it falls, and so wouldn't it fall at a greater force?

Hi, I have a kinematics problem involving free fall acceleration. I'm not sure how to do this so I was wondering if someone could please give me a hand. Thank you. Question: Water drips from the nozzle of a shower onto the floor 2m below. The drops fall at regular (equal) intervals of...

The frost is on the Pumpkin, it's that time of year. When the girls were little, we would always make caramel apples in October. The REAL kind where you melt the caramels, stick the wooden popsicle stick into the apple and then dunk it into the hot caramel. No using those pre-made apple...

Block on Wall--Does it Fall? A 15 N horizontal force F pushes a block weighing 3.0 N against a vertical wall (Figure 6-25). The coefficient of static friction between the wall and the block is 0.71, and the coefficient of kinetic friction is 0.51. Assume that the block is not moving initially...

I have to make up or find a problem that invovles free fall velocity AND relative velocity! Can anyone find/make up a problem for that? HELP!

Hey, I've been having some problems with finding out the rocket's maximum altitude and was wondering if anyone could help. The question information is: A 200kg weather rocket is loaded with 100 kg of fuel and fired straight up. It accelerates upward at 34.0 for 31.0 , then runs out of fuel...

Hey guys, I'm confused about this problem - On a planet far, far away, an astronaut picks up a rock. The rock has a mass of 5.80 kg, and on this particular planet its weight is 40.0 N. If the astronaut exerts an upward force of 43.3 N on the rock, what is its acceleration? I thought you...

A box of mass 12.5 kg rests on the flat floor of a truck. The coefficients of friction between the box and floor are mu_s = 0.190 and mu_k = 0.150 . The truck stops at a stop sign and then starts to move with an acceleration of 2.19 m/s^{2}. If the box is a distance 1.79 m from the rear of the...

Here's the question: A ball is dropped from rest from the top of a cliff that is 24 m high. From ground level, a second ball is thrown straight upward at the same instant that the first ball is dropped. The initial speed of teh second ball is exactly the same as that with which the first ball...

Hi, Can someone please check my work and tell me where I am going wrong? Rain is falling vertically downward with a velocity 25m/s. A cyclist is moving from North to South vith a velocity 15m/s. What is the velocity of the rain with respect to the cyclist? What is the direction the cyclist has...

"An Account of the Fall Of a Meteoric Stone..." This is a very interesting series of letters followed by a chemical analysis, concerning a meteor that exploded over South Africa in the 1830's. I happened to find it when searching for articles by M. Faraday in the archives of the Royal...

Hello, I'm not particularly looking for the answers in this problem as much as I am looking for the method to the solution. It's been giving me a headache. 1. Traumatic brain injury such as concussion results when the head undergoes a very large acceleration. Generally, an acceleration...

A rock is tossed straight up with a velocity of +20m When it returns, it falls into a hole 10m deep. What is the rock's velocity as it hits the bottom of the hole? So basically it is asking for the impact speed right? So that would be Vf^2=Vi^2 +2adelta(s) Vf^2=0+2*9.8*30.41 Vf^2=24.41 It...

Lets say you have a piston falling in a long cylinder. The piston weighs 100kg but only weighs 1kg under water. The cylinder is filled with water, but there is plumbing going from the bottom of the cylinder to the top. As the piston falls the water can move in a continuous loop, from the bottom...

free fall or what??!? I would like to know, if we are on a lift going upwards, and we happen to be standing on a weighing machine, why does our the value appears more than when we just weigh in the stationary lift??

Ok what do they do? How do they let the girl to know that? I mean for sure they don't tell the girl that they love her the moment they feel obssed with her. For sure it takes some time for them to let her know about their interest! I'm really terrible in knowing that. I don't want to be like 1...

Hello all, I've been having some problems regarding the fall of an object in the vertical direction that has air drag which varies quadratically with speed. The problem is as shown: A gun is fired straight up. Assuming that the air drag on the bullet varies quadratically with speed. Show...

We should have an award for the best fall guy, for me it would be a hard choise between Cyrus and penquin. :smile:

This is a basic question I always had trouble understanding. As moon is orbiting earth, is it coming close? Now it might be for other factors but my point is, Earth has some gravity force on it so even if something is orbiting earth, it should be coming to close to it unless it is fast enough...

Quenstion about netwonian mechanics. We have a small body that is moving against a very massive object with big density. For a given time t i want to know what can be the maximum distance of this object. So we have the mass of the big object M , the mass of the small m with speed Ua and the...

transfer student here coming to UCLA fall 2006 as EE major...anyone else comin to UCLA? good to network

scheduled for release by Houghton-Mifflin in September https://www.amazon.com/gp/product/0618551050/?tag=pfamazon01-20 The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next I think the reference must be to the rise of an exclusive string research...

Whenever I see footage of divers, free falling off a cliff into an deep ocean inlet, I empathize the sensation of danger they are facing. This prompted a question in my mind, that applies to both physics and biology. If the water is plenty deep and there are no obstructions between the cliff...

Hello, I am having some difficulty choosing a course to take for this fall. The course is to fill in my technical elective. I am already filling in my other tech electives with an advanced electronics class (with lab), advanced digital (with lab), and opto electronics (with lab). Now, I just...

Hi, I just recently posted this on the astrophysics forum but thought it would probably not quite fit so i decided to move it here. Hi, this is my first post. I have been trying to find an answer out of my own interest but is unable to do so. while searching I found this wonderful website. I...

i have this problem i can't seem to get i think i am overthinking but just can't get it what is. this is a one dimensional motion with constant acceleration.what is the acceleration of a space capsule fired from a 220m long cannon with a launch speed of 10.97km/s

If i have a barometer which reads 76cm of hg when kept in an elevator when the elevator is at rest . now the elevator starts going up with some acceleration . will the barometer read less than , greater than or equal to 76cm of hg . also explain why . what will happen if the barometer is under...

On planet Tehar, the free fall acceleration is the same as that of Earth, but there is also a strong downward electric field that is uniform close to the planet's surface. A 4.05 kg ball having a charge of 4.65 \mu C is thrown upward at a speed of 22.2 m/s, and it hits the ground after an...

why electron doesn't fall into nucleon in a atom?you know e has negative charge and nucleon has positive charge and they're very close in a atom, so why not?:confused:

EDIT: Thanks Hootenanny and Doc Al for looking and trying the problem. I figured out my mistake h_2 = h - \frac{h}{n} not h_2 = 1- \frac{h}{n} I've been working on this for a sick amount of time, please help me figure out what I'm doing wrong... The question is: Spiderman steps from the...

If it takes an object at distance x from the surface of the Earth 17.5 hours to fall from space onto the surface of the Earth, how can we calculate x? The object initially has zero speed. I find this question hard because I've only done problems involving acceleration as a function of time...

The equation for free fall at the surface of the planet Quixon is s = 3.8t2m with t in sec. Assume a rock is dropped from the top of a 400-m cliff. Find the speed of the rock at t = 6 sec. The problem is.. i don't know if the "m" is part of the equation or not.. like should i plug in the 400 as...

Since the nucleus of an atom is +charged and the electron is -charged, why doesn't at least one electron fall into the nucleus?

I recently saw an article in the paper about a woman who was sky diving and was unfortunate enough to have her parachutes fail. Information released about the situation said she fell from 30,000 FT was traving and 80km/h and landed in a concrete parking lot. Anyone have ideas how this was...

Why doesn't water fall down from a bucket while rotating it upside down? Also: 1)What causes sound when bombs explode? Is it the quick heating of air and compression something like sonic boom 2)How do the ariel fireworks go up and explode?

Heavier objects fall faster...myth or fact? (I'm not too good with history so correct me if I'm wrong.) pre-gallileo this is what people generally assumed. Gallileo actually did some experiments to show that all objects fall at the same acceleration. Then Newton provided the math and it was...

A roof tile falls from rest from the top of building. An observer inside the building notices that it takes 0.20 s for the tile to pass her window, whose height is 1.6 m. How far above the top of this window is the roof? I attempted this question about 2 or 3 different ways but they don't...

Heres the question: an 32.8 Newton object is in free fall.what is the mangniutude of the object if it encounters air resistance of 16.6 Newtons? I think you subtract cause air resistance cuts down force: 32.8 - 16.6 = 16.2 Newtons So am i right or do i need to use another equation?