Falling Definition and 1000 Threads

When replying to this thread: https://www.physicsforums.com/threads/the-nasa-zero-gravity-flight.927136/ I became uncertain of my understanding of the physics after the plane starts to descend. What I imagine happens is that your forward velocity would remain constant and you would be...

Homework Statement Captain American bails out of an airplane and falls 50 meters without friction. When the parachute opens, he decelerate at 2.0m/s2. He reaches the ground with a speed of 3.0 meters/sec. a.) How long is captain america in the air? do= d= vo= v=3m/s t= ? a= -9.8m/s2 ?? (this...

Unfortunately I didn't find a thread discussing this issue. First I will sketch the standard argument that one should not use the rocket engine and try to accelerate away from the singularity. Then I will try to identify the problematic part of this argument and ask for your comments. 1) For...

Homework Statement i know problems of this kind have been posted a lot but i have a few of my own questions please take a look at them thanks i am having several conceptual errors in rotational dynamics one of them is : since the rod is massless must there be net zero force and torque...

Homework Statement Roger sees water balloons fall past his window. He notices that each balloon strikes the sidewalk 0.83 s after passing his window. Roger's room is on the third floor, 15 m above the sidewalk. Part A: How fast are the balloons traveling when they pass Roger's window? (express...

Homework Statement A ball is thrown straight up from the edge of the roof of a building. A second ball is dropped from the roof 1.00s later. You may ignore air resistance. If the height of the building is 20m, what must the initial speed of the first ball be if both are to hit the ground at the...

A marble is released at 22.5 meters per second from a 70 meter tall platform. When will the marble strike the ground if the equation for the platforms height is 2.3[t][/2]+ (-)6.5t+70?

Hello! Imagine you drop a steel ball of weight x from a variable height y. the ball hits a steel ramp on the ground which is at 45 degree's I would like to know how I could work out how far away the ball will land. I have had a good look around for this however the closest thing I can find...

Homework Statement Because of the Coriolis force, falling objects on the Earth are deflected horizontally. For instance, a mass dropped from a tower lands to the east of a plumb line from the release point. In this example we shall calculate the deflection of a mass m dropped from a tower of...

If two people are free falling from the sky at the same (high) speed, at the same altitude, but about 20 meters away from each other, and one of them has a gun and tries to shot the other, do they aim directly at the other person so they get a hit (because the bullet would also be falling), or...

Hi! I'm thinking how would the velocity of a sphere change if it falls from rest in a tall beaker full of oil. I know that the direction of acceleration is upwards, and the acceleration should be decreasing at a decreasing rate. But how would the velocity change if the velocity is initially zero...

Hi In a school interview the physics teacher me why a rope attached to the top of a cliff, which would support a climber's weight while dangling gently, would break if the same climber fell from a height while attached to the rope. Im guessing it's due to increased momentum but the rope...

Homework Statement [/B] http://imgur.com/a/Ssolz Homework Equations [/B] Elastic Collision so $$ mgh = \frac{1}{2}mv_i^2 = \frac{1}{2}mv_f^2 + \frac{1}{2}I\omega^2 $$ $$ F=ma $$ The Attempt at a Solution [/B] So the problem is similar to this one which allows me to work out the normal force...

I have analysed some roulette spins with sony vegas in order to get the time for each turn of the ball. It is supposed that if the time that takes for the ball to complete a turn is higher, it means that its velocity is faster and thus the time at which it will fall off from the rim will be...

Homework Statement A ball is dropped from somewhere above a window that is 2.00 m in height. As it falls, it is visible to a person looking through the window for 200 ms as it passes by the 2.00 m height of the window. From what height above the top of the window was the ball dropped? Is...

I'm trying to figure out how much energy needs to be absorbed, radiated or displaced from an object falling from various heights. To make this clear, the "item" is a person so the weight can vary from 70-350lbs and the height let's say 60-3500 ft. Obviously the speed at the end will determine...

Hello, I found a derivation on NASA and several others that say something different. Can someone tell me which is correct? They differ by a factor of 3. This is confusing because some places say an object falling from 100m should deflect by 3cm but NASA says .16mm. Those are more different...

If there is a ball falling from a height due to gravity, and you keep your hand still and let the ball fall onto it, it stops suddenly and makes a loud noise. However, if you lower your hand as you catch the ball, like when a cricketer catches a fast moving ball, the catch is almost silent. I...

Homework Statement [/B] A small steel-bearing falls 25.0 cm in glycerol in 23.8 s and the same distance in castor oil in 15.1 s. The densities are for glycerol 1260 kg m−3 , for castor oil 961 kg m−3 , and for steel 7830 kg m−3 . The viscosity for glycerol is 1.490 Pa s. Calculate the viscosity...

Hey guys I have a question. Terminal velocity is 9.81mps correct? Which converts to basically 35kmph so does that mean hitting the ground from free fall after jumping out of an air plane would have the same effect as hitting a wall or something immobile and hard at 35kmph? Thanks

Well, first of all i want to apologize about my english skills hahaha I have been trying to calculate a time formula for free falling object through large distances (or weak gravitational fields) and my results don´t have much sense (I test my results in a quite realistic game called Algodoo)...

Homework Statement A cantaloupe with a mass of 0.45 kg falls out of a tree house that is 5.4 meters above the ground. It hits a tree branch at a speed of 6.3 m/s. How high is the tree branch from the ground? Homework Equations ## \Delta h = \frac {v_i^2 - v_f^2} {2g} ## The Attempt at...

1. Question Given an idea spring with constant K, a mass of M is dropped onto the spring from a height of H1. The spring compresses D distance. We take the mass off, and drop the mass again at a height of H2, where H2 is significantly greater than H1. This time, will the spring compress a...

Homework Statement [/B] My physics teacher - "You may like this question, its very structured" Calculate the distance a slate tile falls from a roof The roof is angled at an angle 30 degrees. mass of slate tile is 0.8kg The length of the roof is L=6m The height of the roof above the ground is...

Homework Statement Marian, who is standing on her balcony, is surprised by a pigeon and throws a flowerpot up in the air at 2.1 m/s. It takes 3.0 s for the flowerpot to smash to the ground. The flowerpot experiences acceleration due to gravity of 9.81 m/s [down]. a) How high is Marian’s...

Homework Statement Homework Equations 0=viscous+gravitational+pressure I saw in the solutions that pressure=0 in this case, but why? I also knew that : accumulation= flow in - flow out+generation, why not use this one? The Attempt at a Solution (their solution) We are interested in...

If I fall into a Schwarzschild black hole and, as I'm falling, look in the direction away from it, what do I see? I once heard someone say the rest of the universe would appear to move faster and faster, and as I cross the event horizon it would appear to move infinitely fast. I'm not sure...

When a mass is in a circular motion and suddenly gets released by its centripetal force, it will continue traveling in a straight path (tangent to the circle and perpendicular to the radius in the moment of release) if no other forces acting. So let’s make a case: We have a space centrifuge...

How do we know that the stars we see, or some of them are not the light from our own system falling back, and that we may be looking at light from our own star/solar system/ galaxy that has taken millions of years to fall back on its point of origin?

I saw some of these videos showing feather and some balls falling with the same speed in vacuum. But on normal atmospheric pressure they fall depending on their weight. This is just blowing my mind, WHY is this ? Does this prove Newtons Law of Gravity is wrong ? Then how is Einstein's...

Harvard University has an interesting article on a rod whose end that falls faster than gravity around a pivot. http://sciencedemonstrations.fas.harvard.edu/presentations/falling-faster-g How did they derive this formula? Where R is length of rod/2, or the centre of mass. Why did they use...

I heard that you can not survive a fall into water at a height of 250 feet or higher. I have also heard that the reason for this is it acts like concrete at the speed you would be traveling. My example scenario is kinda odd but goes like this. You are a paratrooper. You have just jumped out of...

I just started reading general theory of relativity. I have some elementary questions. Not an english speaker so bear with me. I am reading the thought experiment which describes path of a photon in a free falling lift. For an observer inside the lift, the photon path is a straight line. But...

Homework Statement A ring of mass M hangs from a thread, and two beads of mass m slide on it without friction, as shown. The beads are released simultaneously from the top of the ring and slide down opposite sides. Show that the ring will start to rise if m > 3M/2, and find the angle at which...

If you fall down an escalator going up, do you ever stop falling?

Homework Statement An object with mass of m traveling in a circle rail ,when reached point A the object derailed and moved in a parabola path to point B and so on find the length of AB in term of R and theta. given that B is on the same horizontal level as A Homework EquationsThe...

Hello, I am building a bicycle with suspension on it. The rear wheel is connected to the bike via an axle on a swing arm (a long lever), connected to a linkage lever which is connected to a shock, which has a spring on it. Ultimately I'm trying to calculate the force applied to the shock...

I realize that this question has been asked many times on this forum, however, I have yet to come across a satisfying/understandable answer that takes into account gravitational time dilation. Premise: The speed of light inside a gravitational field is slowed down relative to a distant observer...

So a ball is rolling off a cliff. The red is the proper acceleration and the blue is the geometric acceleration. How is it in the rain frame that the surface is moving down initially? Consider the situation where a rain drop falls straight down, with no ball rolling, just the ground right...

I will ask the question first and give the reason why I'm asking after. Question: Approximately how fast can a 5'11" tall man weighing 195 lbs. fall towards the ground if he's 3 miles above the surface and has control over the winds of a category 5 hurricane storm to propell him downwards...

Can anyone explain this "mathematically"? i.e. how to calculate the time in each cases?

Homework Statement A rope of length L is falling off an incline. Part of the rope is still on top of the horizontal surface. There is no friction between the incline and the rope. The incline is at an angle theta above the horizontal. a) What is the magnitude of the acceleration of the rope...

Homework Statement A frictionless pulley has the shape of a uniform solid disk of mass 2.50 kg and radius of .2 m. A 1.50 kg mass is attached to a very light wire that is wrapped around the rim of the pulley, and the system is released from rest. a) How far must the stone fall so that the...

Homework Statement I am trying to develop simulation for a falling object subject to air resistance. Object is similar to Samara seed. object is considered to be under steady vertical descend. know variable : surface area of object (A) weight of object (W) cd: drag coefficient object rotates...

Homework Statement My problem is trying to understand this graph and explain why it changes the way it does Homework Equations [/B] e=change in ∅/change in time The Attempt at a Solution [/B] I know that the magnetic field increases/decreases when the magnet is on the way into the coil and...

Homework Statement a man slides off a roof that makes an angle of 45 degrees below the horizontal. friction and air resistance neglig. he slides 4m, falls off and lands a certain distance away from the building. another man stands 4m away and is 1.2m tall. how far from the building does the...

Homework Statement A pendulum is swinging inside a lift. What happens to the bob if the lift cable breaks when the bob is at the lowest point? Homework EquationsThe Attempt at a Solution When I consider the bob relative to the lift, the bob is apparently weightless. There should be no net...

Hi All, Long time absentee from the forums hoping for some direction in my new research. I've been tasked to look into the stages of motion of objects (dropped from various heights), hitting a body of water (of various depths) and eventually hitting the seabed (of various sediment types). I am...

$\tiny{205_o6_05_velocity}$ The equation for a free fall at the surface of celestial body in outer space ($s$ in Meters, $t$ in seconds.)\\ is $\displaystyle s=2.38t^2$ How long does it take a rock falling from rest to reach a velocity of $\displaystyle 25.7 \frac{m}{sec}$ on this celestial...

Homework Statement Let's have a disk of mass ##m## and radius ##a## and massless rope tangled in it. One end of rope is tied to the ceiling and the disk is falling freely down. System has one degree of freedom. As a coordinate we can choose angle ## \phi## which says an angle of rotation from...