Fall Definition and 921 Threads

Homework Statement What is the threshold or percent accuracy (100% like plus-minus 10%) of a freefall with air resistance? Homework Equations % accuracy = (actual_free_fall_time)/(ideal_free_fall_time) Computed Free Fall Time based on 9.8m/s^2 net force towards the ground. Actual...

I'm a 3D artist and I'm making an animation that involves a free falling object. I know that, in a vacuum at least, an object will fall 32 feet during the first second; during the second second it'll fall 64 feet -- a total of 96 feet after only two seconds of free falling. The problem is that...

Even here in San Diego there is a Fall temperature drop that does an evil thing to your appetite. Last night I broke into a barn, ate four horses, a sack of corn, and then attacked two Halloween pumpkins from the farmer's front porch for dessert. Between meals all I want to do is sleep.

can some one help me write out my lab for this experiment?. I've done the experiment and i have my data and graphs and charts etc. i just need help in the order format and wording. thanks.

Homework Statement A stone is dropped from the roof of a high building. A second stone is dropped 1.50 s later. How far apart are the stones when the second one has reached a speed of 11.0 m/s? Homework Equations kinematics The Attempt at a Solution i need help setting up the...

Homework Statement A parachutist descending at a speed of 20.0 m/s loses a shoe at an altitude of 20.0 m. (Assume the positive direction is upward.) a)When does the shoe reach the ground? (seconds) b)What is the velocity of the shoe just before it hits the ground? Homework Equations i...

I have no idea how to even begin this problem: At the beginning of a basketball game, a referee tosses the ball straight up with the speed of 4.6 m/s. A player cannot touch the ball until after it reaches its maximum height and begins to fall down. What is the minimum time that a player must...

Homework Statement A hot-air balloon is descending at a rate of 2.0 m/s when a passenger drops a camera. If a camera is 45m above the ground when it is dropped, (a) how long does it take for the camera to reach the ground(b) what is the velocity just before it lands? Let upward be the...

Homework Statement Two ball are dropped from 5m high, Use 10 m/s^2 for the magnitude of the acceleration due to gravity. Homework Equations How do i start? The Attempt at a Solution not sure on how to start so i haven't attempted:(

Homework Statement A bolt is dropped from a bridge under construction, falling 98 m to the valley below the bridge. (a) In how much time does it pass through the last 30% of its fall? (b) What is its speed when it begins that last 30% of its fall? (c) What is its speed when it...

Homework Statement A hot-air balloon is ascending at the rate of 13 m/s and is 90 m above the ground when a package is dropped over the side. (a) How long does the package take to reach the ground? (b) With what speed does it hit the ground? Homework Equations The...

Homework Statement Divers in Acapulco, Mexico, leap from a point 36 m above the sea. What is their velocity when they enter the water? Homework Equations V^2=u^2+2as, probably wrong. The Attempt at a Solution s=36, u= 0, Find Final Velocity, a= -9.8 , I get some ridiculous...

I’m an electrical engineer. When explaining gravity in GR terms to my peers, and I get to the part about there being no net force acting upon an object that’s “free falling” in curved spacetime, I have difficulty countering the argument: “Yeah, you can’t measure a net force because gravity is...

if a 2 kg ball is thrown upward at a speed of 22.2 m/s and it hits the ground after 4.10 s, can I use this information to find out when and where it is at the apex? Does the mass come into play, or is it the same for all objects? Thanks.

Homework Statement A parachutist of mass 80 kg approaches the ground at 5 m/s. Suppose that when he hits the ground, he decelerates at a constant rate (while his legs buckle under him) over a distance of 1 m. What is the force the ground exerts on his feet during the deceleration...

I'm really bad at physics and never have time for study groups and was wondering if you guys/gals might be able to help me out with my problem. If a person steps off a building of height h, and free falls on the way down to the bottom. What is the height of the building if he falls a distance...

1) To test the quality of a tennis ball you drop it onto the floor from a hieght of 4 m. it rebounds to a hieght of 2 m. if the ball is in contact with the floor for 12 ms, what is the magnitude of its average acceleration during contact and is the average acceleration up or down. What i did...

1) A lead ball is dropped into a lake from a diving board 5.12 m above the water. It hits the water with a certain velocity and then sinks to the bottom with this same constant velocity. It reaches the bottom 4.72 s after it is dropped. (Assume the positive direction is upward.) How deep is the...

(moved to Intro Phys... - Doc Al) ---------------------------------------------------------------------- Hi guys, this is my first post in this forum. I feel lucky to come across a place like this and even more thankful if i can get help on this problem that I've been spending a loooot of...

Hello, If free fall is defined as falling with the absence of friction, then what interactions does an object participate in if it falls with friction? The first obvious answer is that the object participates in a contact friction interaction with the air (or air friction). The second answer...

Homework Statement Determined to test the law of gravity for himself,a student walks off a skyscraper 200 m high, stopwatch in hand and starts his free fall (zero initial velocity. Five seconds later, superman arrives at the scene and dives off the roof to save the student. a.) What must be...

Posted on reddit. Does he translate a partial amount of vertical energy into horizontal energy? when he bends his knees, he seems to "push off" before he hits the ground. I can definitely believe he timed it, and that he has enough coordination / gusto to come up with a life-saving plan in...

I'm going to be a junior transfer next fall and I'll be starting my upperdiv classes. I'm a physics major, but am undecided about which area of physics I want to pursue, though I am leaning towards particle, astrophysics, or optics. Also unsure about theoretical or experimental physics. I...

If you drop a metal ball and a feather at the same time the ball will touch the ground before the feather, why is this? What effect is the Earth's atmosphere having on the feather? If you dropped a piece of metal in the shape of a feather it still would touch the ground before the feather and...

1. IF there are two objects, one is heavier, the other is lighter. Now someone drops them both from the top of a building, which object accelerates faster? do they both have the same acceleration that comes from the earth? 9.81m/s^2? or we use the formula net force=mass* acceleration which the...

I just finished reading Black Holes by E. Taylor and J. Wheeler. Throughout the book they use the SC metric for the the metric near a massive object(for radial motion only: d \tau^2 = \left( 1 - \frac{ 2M }{r} \right) dt^2 - \frac{dr^2}{\left( 1 - \frac{ 2M }{r} \right)} Where dt is measured...

I am not so clear about the definition of 'free fall'. If an object is an example of free fall, then must its acceleration be 9.81m/s^2? For example, if a sky diver jumps from an airplane, because Earth has atmosphere, the rate of acceleration decreases due to air resistanc. so now the...

Clouds seem oblivious to Earth's gravity and show absolutely no tendency to fall to the ground. Yet they are comprised of water droplets many times the density of the surrounding atmosphere, and therefore defy the laws of floating bodies. It might be argued that the viscosity of the air and air...

A. Here is the stated inquiry: A man jumps to a vertical height of 2.7 m. How long was he in the air before returning to Earth? B. Equations used: Y = Yo + VoT + (1/2)gT2 (Y because motion is in the vertical direction) C. Attempted solution: Because the total...

Homework Statement This is not a numerical problem. A body floats in a liquid contained in a beaker. The whole system falls freely under gravity. The upthrust on the body due to liquid is: 1. zero 2. equal to weight of the liquid displaced 3. equal to the weight of the body in air 4...

Homework Statement A woman is reported to have fallen about 139 ft from the 17th floor of a building, landing on a metal ventilator box that she crushed to a depth of 20 in. She suffered only minor injuries. (a) Ignoring air resistance, calculate the speed of the woman just before she...

can someone explain to me in simple language why does not Moon fall on the Earth? I don't understand it why? please don't give me wikipedia link or something like this http://www.teachersdomain.org/resources/ess05/sci/ess/eiu/moonorbit/index.html wich I find wery funny thanks

For my first semester at the University of Arizona --------------------------------- MATH223 - Vector Calculus PHYS151 - Intro to Mechanics ENGL101 - First Year Composition TRAD104 - Science and Inquiry --------------------------------- 14 credits I'm thinking about adding a German...

Why objects with different mass fall with same velocity?? It is long said and proven that objects with different mass free-fall with same velocity. Suppose the mass of Earth is M and mass of an object in free fall is m1. As we know Earth's gravitational acceleration constant is g = 9.8m/sec2...

Homework Statement In part (a) of this question suppose a stone is thrown verically upward with a speed of 12.9 m/s from the edge of a cliff and that h = 82 m. At what speed (in m/s) does the stone hit the ground? Homework Equations T = v/g Free fall equation V = (V^2 - 2gvt ...

Homework Statement The plane of a 20cm x 20cm metal loop with a mass of 10g and a resistance of 0.010 ohms is oriented vertically. A 1.0 T horizontal magnetic field, perpendicular to the loop, fills the top half of the loop. There is no magnetic field through the bottom half of the loop. The...

Free fall Experiment Help! 1. Homework Statement Experiment:- OBJECTIVES In this experiment you will investigate the motion of a freely falling body on a fictitious planet. You will discover for an object that falls from rest (1) the value of the acceleration due to gravity on the...

A ball is thrown upward from the top of a 25.4-m-tall building. The ball's initial speed is 12 m/s. At the same instant, a person is running on the ground at a distance of 32.0 m from the building. What must be the average speed of the person if he is to catch the ball at the bottom of the...

Why does in QM the electron does not fall toward the nucleus? After all, the only force between nucleus and electron is attractive (- electron and + nucleus). Is the same reason that justifies the moon does not fall to the earth?

Next semester, Fall '07, I'll be taking a couple math courses for my math major. Could you guys give me some advice on whether or not the workload is too much? Here is my schedule: Discrete Math (4 units) Number Theory (4 units) Electrodynamics & Kinetic Theory (3 units) Capstone Prepatory...

"Under what conditions does a geodesic represent a possible wordline for a particle in free fall, parametrized by proper time." I can only think of one conditions - the fact that the metric ds squared is positive. Is this enough?

I have 2 question about the Archimedes principle? 1. does it hold in a vessel in a free fall? why? 2. if we imppressed 2 same hollow bodies in water, and just one of them has a hole at the bottom. which one is more difficult and why? thank you!

Homework Statement If a person is sitting in a train which's starting from rest & he throws a ball upward,then where'll the ball fall? 1)At the position where it's thrown? 2)Behind the person? or 3) Ahead him? Thanks. Homework Equations Nill. The Attempt at a Solution May...

For as long as I can remember I have had this sensation (and before you ask, I am not smoking anything). The feeling only occurs when I am in bed and starting to fall asleep, the only way to describe it is a strange feeling of big and small at the same time. It’s like a very tiny dust particle...

I'm having trouble with a particular law, the one that says "heavier objects DO NOT fall faster" Now all experiments I've read were conducted or theorized in an atmoshere. This variable must be removed. To see the correct interaction of 2 different bodies of mass one must experiment in a vacuum...

Hi : See https://www.physicsforums.com/showthread.php?p=1253898&posted=1#post1253898 Please,make comment. How would you calculate the terminal velocity ,in the turbulent flow,for a spherical rigid object?

A 575 kg satellite is in a circular orbit at an altitude of 550 km above the Earth's surface. Because of air friction, the satellite eventually falls to the Earth's surface, where it hits the ground with a speed of 2.10 km/s. How much energy was transformed to internal energy by means of...

Problem 1 Homework Statement A diver springs upward with an initial speed of 1.8 m/s from a 2.5 m board. (a) Find the velocity with which he strikes the water. (Hint: When the diver reaches the water, his displacement is y = -2.5 m (measured from the board), assuming that the downward...

I have been having some problems with this question: An object falls from a height h from rest. If it travels a fraction of the total height of 0.5665 in the last 1.00 s, find the time of its fall. I started by saying h=(0.5)(g)(T^2) Then I said that 1-.5665h=(0.5)(g)(T-1)^2 I have...

Homework Statement A 60.kg firefighter slides down a pole while a constant frictional force of 300N retards his motion. A horizontal 20.0kg platform is supported by a spring at the bottom of the pole to cushion the fall. The firefghter stars from rest 5.00m above the platform, and the spring...