Falling bodies Definition and 40 Threads

A set of equations describe the resultant trajectories when objects move owing to a constant gravitational force under normal Earth-bound conditions. For example, Newton's law of universal gravitation simplifies to F = mg, where m is the mass of the body. This assumption is reasonable for objects falling to earth over the relatively short vertical distances of our everyday experience, but is untrue over larger distances, such as spacecraft trajectories.

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  1. B

    Cart-Pulley-Hanging Mass Dynamics

    The Setup is the cart-pulley-hanging mass or Atwood machine: if the cart is allowed to fall over the edge, and falls freely with the mass, will the rope tension remain the same as it was before the cart went over the edge? Is this situation the same as if the cart-rope-mass were held aloft by...
  2. M. M. Fahad Joy

    How does halving the time affect the distance traveled by a falling object?

    Homework Statement If a falling object overcome 72 metres in 6 second, how much distance it overcame in first 3 second. Homework Equations s = ut+(at^2)/2 The Attempt at a Solution Here, s = 72 m u = 0 t = 6s a = ? We know, s = ut+(at^2)/2 Or, 72 = 0*6 + (a*6^2)/2 Or, 72 = 36a/2 Or, 72 = 18a...
  3. artriant

    Falling apple inside a space centrifuge

    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...
  4. A

    Falling Feather and ball in vacuum

    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...
  5. A

    What is the velocity of a falling object with air resistance?

    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...
  6. C

    Penetration of falling object into sediment (after water)

    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...
  7. A

    Is the Hypothesized Law of Gravity for a Falling Body's Speed Accurate?

    Homework Statement The speed of a falling body might be based on the observation that the velocity of a falling object seems to increase the further it has fallen. Model the hypothesis "The speed of a falling object is proportional to the distance it has fallen" as a differential equation...
  8. T

    Calculating the Velocity and Time of a Freely Falling Rock

    Homework Statement A small rock is thrown vertically upward with a speed of from the edge of the roof of a 30.0-m-tall building. The rock doesn’t hit the building on its way back down and lands in the street below. Air resistance can be neglected. (a) What is the speed of the rock just...
  9. M

    Physics HW- Falling Bodies, Part 3

    Homework Statement The moon is smaller than the Earth and has a weaker gravity. On the moon's surface, the acceleration due to gravity is 1.6 m/s^2. You are on the moon and you throw a moon rock straight up. It reaches a height of 44 m. a) Find the moon rock's initial velocity. b)Find...
  10. M

    Physics HW- falling Bodies, Part 2

    Homework Statement A brick is accidentally dropped from a window of a tall building and falls 160 m to the ground. How long does it take the brick to reach the ground? [b]2. Homework Equations [/b y=y initial+v inital +1/2 (αt^2) The Attempt at a Solution y=0+0+9.8 m/s^2(t)...
  11. M

    How fast does a diver hit the water when jumping off a 30m platform?

    Homework Statement A diver steps off a platform 30m above the water. With what speed does he hit the water? Homework Equations v=intial v+at The Attempt at a Solution I reached an answer of 2.47 seconds, but I can't see how I got there anymore! Is this answer correct? Thank...
  12. C

    Falling bodies and terminal velocity

    Is it correct to assume that two objects, with different masses, dropped from the same height at the same time will fall at the same rate until one of the objects reaches its terminal velocity? What are the applicable equation(s) used to calculate this?
  13. D

    Does required time for free falling bodies is independent of mass?

    In a class at OCW 8.01 Professor Walter Lewin said... "...there are very prestigious physicists who even nowadays do very fancy experiments and they try to demonstrate that the time for an apple to fall does depend on its mass even though it probably is only very small, if it's true but they...
  14. D

    Why all free falling bodies reach the ground at the same time?

    If you drop your shoe and a coin side by side, they hit the ground at the same time. Why doesn't the shoe get there first, since gravity is pulling harder on it?
  15. R

    Contradicting conclusions on falling bodies.

    I was recently thinking about potential energy and I came to two conclusions which contradict each other- 1)When a body is falling from a height, the force of gravity is acting on it in the downwards direction. There is displacement in the downwards direction. So as the force and the...
  16. X

    Total Angular Momentum of 2 connected falling bodies.

    I have two 2 rigid bodies with masses m1 and m2 and Moments of Inertia I1 and I2, they are connected by a free rotational joint at some point, their coms lie at c1 and c2. There's gravity. In the beginning both have some angular velocity \omega_i Questions: - Total angular momentum of the...
  17. C

    Falling Bodies - Does mass play a role?

    Me and a few friends of mine were discussing if mass plays a role in the speed of a free falling body. They argued that equal bodies (same volume, same geometry) with different weights (mass) would fall at different velocities. I defended that mass has no part on the matter, but only air...
  18. chris2112

    Galileo's rule of falling bodies

    Simple question, if the force of gravity is proportional to mass and distance, as in Newton's and Einstein's theories of gravitation, then why do people say that objects with two different masses accelerate at the same rate independent of mass on earth? Can Galileo's rule just be a practical...
  19. L

    Question about falling bodies in orbit and acceleration

    Hello, I’m glad that I found this forum, because there is a question that has been bothering me for some time, and maybe someone on a physics forum like this can set me straight on it. It concerns gravity and acceleration. I understand that when an object such as a space shuttle is...
  20. G

    Question about falling bodies

    What force(s) are at work when a spherical object, rolling down an angled surface, tends to adhere to the surface, if only for a short while? Does such a thing exist or am I playing fast and loose with the laws of nature? Thanks
  21. P

    Free Falling Bodies: Calculating Time for Wrecking Ball

    Homework Statement A wrecking ball is hanging at rest from a crane when suddenly the cable breaks. The time it takes for the ball to fall halfway to the ground is 1.31sex. Find the time it takes for the ball to fall from rest all the way to the ground. I think the formula to use is...
  22. P

    Calculating Displacement of a Diver in Free Fall

    The velocity of a diver just before hitting the water is -10.2m/s, where the minus sign indicated that her motion is directly downward. What is her displacement during the last 1.10sec of the dive? I tried to use dthe x=1/2(Vinitial + Vfinal)t=40.8 but it's wrong, what am i doing wrong??
  23. D

    Changing temperature of falling bodies

    Homework Statement A block of material of mass m and specific heat c falls from height h and reaches speed v just before striking the ground. Its temperature is measured immediately after it strikes the ground. If we ignore any change in temperature owing to interaction with the air, the...
  24. K

    Galileo's Theory of falling bodies problem

    Homework Statement If an object falls five meters during the first interval of time, what is the total distance fallen at the end of the second interval of time? (Galileo's Theory of falling bodies) Homework Equations The Attempt at a Solution I know that at successive intervals of...
  25. K

    Distance traveled at end of second interval: 27m

    If an object falls five meters during the first interval of time, what is the total distance fallen at the end of the second interval of time? (Galileo's Theory of falling bodies) I know that at successive intervals of time the distance fallen is proportional to the odd numbers. So I suspect...
  26. D

    Differential free falling bodies

    (i) how you solved this problem, An object of mass 10 kg is dropped from a great height. (a) If the object is subjected to air resistance equivalent to 10 times the instantaneous velocity, find the velocity. (b) How far does the object drop after 5 sec? (ii) what you got as a solution...
  27. P

    Why does a falling object hit harder despite having the same force?

    I posed this question to my teacher: I have a 2 kg object and it sits at rest on the floor. The force is mass * acceleration, so it's about 20 N. Now I drop the ball from, say, 20 feet above the ground. Same mass, same acceleration, so it has the same force, 20 N; but we know the object hits...
  28. S

    Ball and Runner: Catching at the Bottom of a Building

    Homework Statement A ball is thrown from top of a 25m tall building. The balls initail speed is 12m/s. At the same instant a person is running on the ground at the distance of 31m from the building. What must be the avg speed of the person if he is to catch the ball at the bottem of the...
  29. M

    What Height Does a Ball Reach When Its Speed Halves?

    Homework Statement A ball is thrown straight upward and rises to a maximum height of 18 m above its launch point. At what height above its launch point has the speed of the ball decreased to one-half of its initial value? Homework Equations i don't know. The Attempt at a Solution...
  30. P

    Physics Falling Bodies Question

    Homework Statement A person in a hot air balloon that is rising accidentally drops a can of paint from the balloon. The balloon is moving up at a constant velocity of 4m/s, the distance to the ground is at the moment 4m. Find the time it takes for the can to drop to the ground. Homework...
  31. C

    Calculating Distance and Time for Freely Falling Bodies

    Homework Statement 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 up at the same instand theat the first ball is fropped. The initial speed of the second ball is the same as that with which the fist ball hits the...
  32. B

    Experiment Help: Investigating Freely Falling Bodies

    Experiment Help! Homework Statement We were given this experiment in which we have to investigate the motion of a freely falling body on a fictitious planet. 2. Things we have to do (1) the value of the acceleration due to gravity on the planet, (sucessfully did it) (2) how the distance...
  33. R

    What is the final velocity of a falling body?

    Homework Statement It is possible to calculate the velocity of falling bodies (ignoring air resistance of course) using a gravitational acceleration constant. Assume: You don't know what the resistance is. The object started at rest. You DO know there is downwards motion. You don't...
  34. R

    Elementary physics of falling bodies.

    It is possible to calculate the velocity of falling bodies (ignoring air resistance of course) using a gravitational acceleration constant. If there is some other resistance, other than air, is it reasonable to simply reduce the acceleration by some amount to account for that resistance, if...
  35. W

    How can I find the height and time of a freely falling object?

    If someone could please help me with the following question I would greatly appreciate it. An object falls a distance h from rest. If it travels 0.5h in the last 1.00s, find the time and the height of its fall. Ok, so for the second half that the object is falling, the velocity is 0.5h...
  36. S

    Vectors of Freely Falling Bodies

    Ok guys, here is a question I have about freely falling bodies. I did do the questions but my answer just doesn't seem right to me, I don't think I went about it the right way. I will show what I did below the question: Determined to test the law of gravity for himself, a student walks off a...
  37. R

    How High Would a Pellet Reach if Fired Upward from a Cliff?

    Hey all - I have tried and tried to work this problem but I guess I am missing something (I can submit my answer several times to see if I am right and I have been wrong every time) - Here is the problem - A pellet gun is fired straight downward from the edge of a cliff that is 13 m...
  38. A

    Galileo’s law of falling bodies ?

    Galileo’s law of falling bodies ?? hi everybody, I want to know about the mathematics of deriving this laws. or in another word I want to know how did he find it.. Ali
  39. B

    Falling Bodies with air resitance

    I know this may be seen as a physics question and it is, but i am just looking for an explicit solution to falling bodies with air resistance. OK many of you are probably familiar with the equation for a body falling with air resistance. mdv/dt=mg-kv^2 I am not sure exactly how to...
  40. R

    Why Did Heavier Masses Fall Faster in My Atwood's Machine Experiment?

    I used atwoods machine to test the affect of mass on the speed of falling bodies. My research said objects fall at the same rate no matter their weight. When I tested this on Atwoods machine heavier masses fell faster. Can someone tell me why?
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