What is Falling object: Definition and 174 Discussions

In Newtonian physics, free fall is any motion of a body where gravity is the only force acting upon it. In the context of general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it.
An object in the technical sense of the term "free fall" may not necessarily be falling down in the usual sense of the term. An object moving upwards might not normally be considered to be falling, but if it is subject to only the force of gravity, it is said to be in free fall. The Moon is thus in free fall around the Earth, though its orbital speed keeps it in very far orbit from the Earth's surface.
In a roughly uniform gravitational field, in the absence of any other forces, gravitation acts on each part of the body roughly equally. When there is no normal force exerted between a body (e.g. an astronaut in orbit) and its surrounding objects, it will result in the sensation of weightlessness, a condition that also occurs when the gravitational field is weak (such as when far away from any source of gravity).
The term "free fall" is often used more loosely than in the strict sense defined above. Thus, falling through an atmosphere without a deployed parachute, or lifting device, is also often referred to as free fall. The aerodynamic drag forces in such situations prevent them from producing full weightlessness, and thus a skydiver's "free fall" after reaching terminal velocity produces the sensation of the body's weight being supported on a cushion of air.

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  1. L

    To find mass of falling object

    A friend asked this question and it got me thinking.. and I can't seem to think of any solution. :bugeye: Out of curiosity, he asked me.. is it possible to find the mass of a free falling object without knowing the force it hits the ground? (assuming we know the displacement s=0.91m, v=...
  2. C

    Solve Free Falling Object: Find Height of Ball

    Homework Statement A ball, dropped from rest, covers three-fifths of the distance to the ground in the last second of its fall. From what height was the ball dropped? The Attempt at a Solution I have spent the past thirty minutes attempting to figure this out. I initially used a kinematic...
  3. A

    Which Distance is Correct for a Free Falling Object?

    I have a simple question may sound stupid for most of you: For a free falling object v=9.8 m/sec. which of the distance traveled per sec is correct: Formula 1: d = vt d = 9.8/1 = 9.8 m Formula 2: d = 1/2 a*t^2 acc of a free falling object is 9.8m/sec^2 d = 1/2 9.8*1^2 d =...
  4. D

    How Fast Does a Trebuchet Counterweight Travel?

    Hey Smart Guys, At age 61, I am building a mechanical launching device (Trebuchet) and I need to know how fast my counterweight will be traveling. How fast will it be traveling after 1 inch How fast will it be traveling after 60 inch How fast will it be traveling after 120 inch Also, please...
  5. T

    Falling Object And Sound Takes 3.2sec

    Homework Statement A rock is dropped from a sea cliff and the sound of it striking the ocean is heard 3.2s later. If the speed of sound is 340m/s, how high is the cliff? V0= 0 A=-9.8m/s2 Ttotal=3.2s Tsound=Y/340 Y0=Height Y=0 (height at sea) Homework Equations Y=Y0+V0T+1/2(-9.8m/s2)T2...
  6. C

    Projectile Motion- Need help with equations to use for a falling object

    Homework Statement A trebuchet misfires and its 450kg projectile falls from the sling at the vertical height of the firing arm, 1) What force will the projectile hit the ground? 2) If the trebuchet is 5.40m tall with the firing arm in the vertical position, how long will the projectile...
  7. R

    MATLAB Analyzing Falling Object w/ Linear Friction: Troubleshooting Code

    It's an object that's falling from rest. The equation takes into account linear friction. in any case, this is is my code or program of whatever it is called: m=80;%Mass of ignorance g=9.8;%Gravity beta=1.6*10^-4;%Given coefficient for air at STP D=.4;%Diameter of Palin, assuming she's a...
  8. W

    Speed of falling object via derivation/integration

    Homework Statement A stone is dropped from rest at an initial height h above the surface of the earth. Show that the speed with which it strikes the ground is v=sqrt(2gh) Homework Equations The Attempt at a Solution I'm just not sure where to get started. I fully understand...
  9. E

    Force of a falling object

    Homework Statement I need to know the force of a falling object. m=1.502 kg v=0.528 m/s (this value is way off from the theoretical which is .9598 m/s) Duration of impact = 0.167 s I have all the variable but my problem is this: This falling object compresses a spring which needs a force of 21...
  10. C

    Work energy theorem for falling object

    Homework Statement A branch falls from the top of a 95.0 m tall redwood tree, starting from rest. How fast is it moving when it reaches the ground?Homework Equations Total work = \Delta KThe Attempt at a Solution I have no idea how to do this problem.
  11. W

    Calculating the Distance Traveled by a Falling Object on an Airplane

    Was given this problem as a homework assignment but I would like to solve it...just need a push in the right direction. An airliner is cruising at a ground speed of 450 knots. A flight attendant, serving drinks, accidentally knocks a bottle off her cart. The distance from the top of the...
  12. Y

    What is the angle of a falling object's velocity after 2 seconds?

    Homework Statement A stone is thrown off a high cliff with speed 30m/s at an angle 0 degrees. At what angle is the stone's velocity 2 seconds after it's thrown. (measired with respect to the horizontal x direction(angle will be negative)) Homework Equations angle = tan(Vy/Vx)...
  13. N

    Calculating the time of an falling object provding with only speed and weight

    Question: A stone is falling from the top of a buliding with 32m/s. Air resistance is so small that it can be neglected. the weight of the stone is 24N. Calculate the time in second which the stone takes to reache the ground.
  14. N

    Calculating the time of an falling object provding with only speed.

    Question: A stone is falling from the top of a buliding with 32m/s. Air resistance is so small that it can be neglected. the weight of the stone is 24N. Calculate the time in second which the stone takes to reache the ground.
  15. J

    Falling object and distance between time intervals

    Homework Statement Gravity on a falling object causes the object to descend a distance of d=4.9t^2, where d is the distance in meters and t is the time in seconds. A bowling bll is dropped from the top of the Eiffel Tower in Paris, France, which is 324 meters in height. If you neglect any...
  16. S

    Kenetric Energys, verolcity and mass of a falling object?

    At t = 0 a rubber ball of mass m is dropped from a height of 10 m. (i) When does it reach the ground? How fast is it moving when it hits the ground? Each time it bounces, the ball looses 20% of its energy. (ii) Calculate the height it reaches on the 1st bounce, and the time at which it hits...
  17. E

    Falling object: time before it reaches the ground and its position

    A flowerpot is knocked off a balcony 20.0m above the sidewalk and falls toward an unsuspecting 1.75-m tall man who is standing below. How close to the sidewalk can the flowerpot fall before it is too lat for a warning shouted from the balcony to reach the man in time? Assume the man below...
  18. 1

    Acceleration of free falling object on planet X

    Homework Statement While on planet X, an object is thrown vertically upward with an initial velocity of 5m/s. If this object returns to the point of release in 3s, what is the acceleration of a free falling object on this planet? Homework Equations a=vf-vi/t The Attempt at a...
  19. S

    Acceleration of falling object on impact

    I have been out of school for a few years so my physics is rusty. I need help figuring something out for my job. I need to know how high I must drop an object so that it hits the ground with an impact of 1000g's. The object is a cylindar and weighs 2lbs. I have been confusing myself. I...
  20. I

    How High and How Long Does a Volleyball Go When Hit Upwards?

    Homework Statement Stephanie hits a volleyball from a height of 0.8m and gives it an initial velocity of 7.5m/s straight up.? a. how high will the volleyball go? b. how long will it take the ball to reach its maximum height? (hint:@ max height, v= 0m/s) Homework Equations im not...
  21. D

    Velocity of a falling object after 1 meters

    Hello, I have got an question. How can I calculate the velocity of an object which I'll drop from a height of 1 meters with a starting velocity of 0 m/s? I did some research myself and found out that I can calculate this with using the following formula: St = 0.5 * 9.81 * t^2 St =...
  22. R

    How Tall Was the Initial Fall in a Physics Problem?

    A freely falling object requires 1.10 s to travel the last 20.0 m before it hits the ground. From what height above the ground did it fall? (Ans. in m.) I am completely lost on modeling this problem. Please help me figure it out.
  23. J

    Falling object and air resistance

    Homework Statement the effect of air resistance is to slow down a moving object. It can be shown that height of a falling object is given by the following Homework Equations y=y0-[t+(e^-bt - 1)/b]g/b a. show that for short times this reduces to the expected expression y=y0-1/2gt^2...
  24. K

    How to Calculate the Distance of a Free Falling Object Without Air Resistance?

    Can somebody please show me how to solve this problem? A flowerpot falls off a windowsill and falls past the window below. You may ignore air resistance. It takes the pot 0.420 s to pass this window, which is 1.90 m high. How far is the top of the window below the windowsill from which the...
  25. V

    Finding time of travel by falling object in drag coeeficient

    Homework Statement An object with mass 10kg is dropped from a height of 200m. Given that the constant k in the equation is 2.5Nsm^-1 mv'(t) = −mg − kv(t) approximately how many seconds does the object hit the ground? Homework Equations v' + (k/m)v = -g The Attempt at...
  26. C

    Falling object 1D Kinematic Question

    Homework Statement An object falls from height h from rest. If it travels .5h in the last second before hitting the ground, determine how long it takes to fall and the height h. xi = .5hm, t =1s, a = 9.8m/s^2, xf = 0m, Homework Equations Vf = Vi + at xf = xi + .5at^2 The Attempt at a...
  27. B

    A falling object of decreasing mass.

    The problem is: A snowball is dropped from the top of a building, evaporation causes the mass m of the snowball to decrease at a rate proportional to the snowball's speed as the snowball falls, so that M' = k * abs(y') where y denotes the vertical distance from the ground and k is a...
  28. J

    Calculating Peak Force of Falling Object with Load Cell and Steel Cable

    I'm running an experiment where I drop a mass (99.7kg) a distance of 1.8m. The load is suspended from a very rigid structure through a steel cable. I currently have a load cell in series with the cable and mass. I acquire data at 1000Hz and my load cell tells me I have a peak force of about...
  29. E

    DE question involving a falling object

    Homework Statement Note that this is a first year, Calculus 12 DE question: The velocity,v, of an object falling through the Earth's atmosphere obeys the DE dv/dt=g-kv, where k is the called the drag constant and g is the gravitational constant. This equation states that the acceleration of...
  30. Q

    How much does a falling object weights ?

    how much does a falling object "weights"? Hi ev. the other day i was asked by a friend that does "aerial silk" (http://en.wikipedia.org/wiki/Aerial_silk, just found out it was called that :P) how much (still) weight should the beam (to which the silk is tied) hold in order to hold her weight...
  31. H

    Can spinning reference frames mimic gravitational fields?

    Hey everyone, THIS IS NOT A HOMEWORK QUESTION. This is a question I think I know the answer to but I want to see what you get to check my answer. Here is the setting. You take an object up into the atmosphere. Far enough away so that the acceleration do to gravity of the Earth is 1 m/s^2...
  32. J

    Falling object - relating distance interval to time interval

    Homework Statement An object falls from the top of a 103.6m high building. The vertical distance between two consecutive windows A and B is 4.0m. The first window/storey is also 4m from the top of the building. The object reaches window B 0.1s after it has reached window A. Which...
  33. M

    Showing that energy of a falling object remains constant

    I got this question on a sample test but I don't know how they want me to answer it Q.) Show that for a falling body, the total amount of energy is constant at any point I suppose I could state the potential energy then draw a graph of how the potential energy is converted into velocity. Is...
  34. P

    Finding velocity of a falling object

    Homework Statement When Mongol drops his ball off the Hasselbluff Mountain Viewpoint, its height above the ground at time t is given by h = 64 - 1/2gt2. How long will the ball take to hit the ground? How fast is the ball going the instant before it hits the ground? Homework Equations I...
  35. S

    The instantaneous velocity of a freely falling object

    What is the instantaneous velocity of a freely falling object 10 s after it is released from a position of rest? What is its average velocity during this 10 s interval? How far will it fall during this time? I had asked a few friends for help and I keep getting mixed answers. v = gt 98m/s...
  36. J

    Using Impulse-Momentum to Find Time of Falling Object

    Homework Statement Use the impulse-momentum theorem to find how long a falling object takes to increase its speed from 5.50 to 9.00 . Homework Equations deltaP = impulse P = momentum (m*v) impulse = J (integral from ti to tf) The Attempt at a Solution 3.5 seconds, though, I knew...
  37. S

    Work done by gravity on falling object

    Homework Statement A 3000 kg space vehicle, initially at rest, falls vertically from a height of 3500 km above the Earth's surface. Determine how much work is done by the force of gravity in bringing the vehicle to the Earth's surface. Homework Equations Gravitational potential...
  38. science_rules

    Understanding horizontal and vertical components of a falling object

    I want to understand this: In the case of a dropped object, the horizontal component of the velocity with which the object hits the ground is not the same thing as the horizontal velocity itself, am i right? The horizontal component of the velocity when the object hits the ground means the...
  39. M

    Differential equation involving falling object

    Homework Statement A body of mass m is projected vertically upward with an initial velocity v0 in a medium offering a resistance k|v|, where k is a constant. Assume that the gravitational attraction of the Earth is constant. a) Find the velocity v(t) of the body at any time. b) Using the...
  40. J

    How High Did the Object Fall If It Took 1.5 Seconds to Drop the Last 30 Meters?

    Homework Statement A certain freely falling object requires 1.50 sec to travel the last 30 m before it hits the ground. From what height above the ground did it fall? Homework Equations The Attempt at a Solution the answer is 38.2, but I cannot figure out what formula to use to...
  41. C

    Can the Force of a Falling Object be Calculated to Test Product Durability?

    I have created a piece of equipment that drops a steel weight, which weighs 5 lb, with a surface area of 1.69 sq. in. The weight can be dropped from 1' all the from 6'. The purpose of the piece of equipment is to test the durability of one of our products. The problem is we do not have the...
  42. P

    Question about the force of a falling object.

    I'm a theatrical lighting designer wear a fall arrest harness while climbing in trussing. I can't find a calculation method for determining the weight put on the anchor point in the event of a fall. I weight 160 lbs. my lanyard is 6 feet long. It has no shock absorber so I would come to a...
  43. D

    Calculating componants of a falling object.

    Im doing a little investation.. nothing too detailed. Its into the way parachutes fall ect. Im dropping parachutes out of a window with different weights on, up to a certain weight where the kenetic energy becomes too high. Then I am going to try to design a better shape to reduce the KE of the...
  44. B

    Understanding Gravity: The Curvature of Spacetime Explained

    My limited understanding of relativity tells me that "gravitational forces" are really just due to the curvature of spacetime. That is, the reason why the Earth orbits the sun is because the Earth is following a "straight" line but the actual spacetime is curved so the "straight" line appears...
  45. B

    Graph of Kinetic Energy v. Displacement of a Falling Object

    [solved] Graph of Kinetic Energy v. Displacement of a Falling Object Homework Statement Draw and label a graph with energy for the y-axis and displacement for the x-axis of the kinetic energy and potential energy of an object in free-fall that started with a horizontal speed of 30 m/s from a...
  46. E

    What is the jerk of a falling object?

    Suppose an object is suspended above the Earth, then released. It immediately accelerates to 32.2 f/s^2. There should be a jerk as the acceleration changes. Is there an experimental method to measure that jerk? Experimental as opposed to just doing the math. Thanks.
  47. 4

    Using Kinematic equations to describe a falling object

    Homework Statement For this project, we had to build a vehicle that would hold an egg, and drop it a distance of about 40 feet, and making sure the egg wouldn't break. There are various parts to the report part of this project, and I had a question about the first part. Basically, one part...
  48. G

    How fast is a falling object going without riction

    An object falls from rest for a distance of 25 m. If there was no air friction, how fast was it going at that distance? I'm not sure but I would imagine v=(25m)(9.8m/s^2)= 245m/s ? which seems quite high to me so I know I am not calculating it correctly.
  49. ~christina~

    Acceleration of free falling object on another planet

    [SOLVED] Acceleration of free falling object on another planet Homework Statement A ball is shot vertically upward from the surface of another planet. A plot of y versus t for the ball is shown in the figure below, where y is the height of the ball above its starting point and t = 0 at...
  50. M

    Help with free falling object problem

    I hope this is the right forum, so I apologize in advance if I'm mistaken. Here's the question poised: How many seconds apart should two balls be released so that a ball being dropped from a height of H reaches the ground at the same time as a ball dropped from a height of 5H? I need...
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