Free fall Definition and 486 Threads

Hey guys, I'm new here and need some help with a physics homework question. Two students stand on top of a building of height (h). One throws a ball straight upward at the same speed as the other student who simultaneously throws a ball straight downward toward the ground. Which of the...

Forgive a question from a mere piker in GR who has got interested in something he can't find the answer to: What is the metric and coordinates for a radial free-faller in Schwarschild? Let's specify we drop him radially from some r0 and he sets his clock to 0 and drops. I'm imagining...

A ball is thrown vertically upward from the ground with an intial speed of 15m/s. How long does it take the ball to reach its maximum altitude? What is its maximum altitude? Determine the velocity and accelartion of the ball at t=2s. If anyone can help me with the relatively simple problem...

[SOLVED] Free Fall Gravity Question question below

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...

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...

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...

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...

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 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 ...

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...

"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!

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?

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...

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...

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...

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...

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...

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...

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...

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??

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...

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

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...

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...