Falling Definition and 1000 Threads

Homework Statement An elevator ascends with a constant speed of 2.5m/s. A loose bolt drops from the ceiling of the elevator which is 3.0m above the floor. a) How long does it take the bolt to fall from the ceiling to the floor of the elevator? b) What are the displacements of the bolt...

sorry if the title is not clear, if you have a better idea i'll change it. say i drop a 10kg book to the floor. when it reach the floor, the floor stops it by "activating" the Normal force on it... my question is, how much time does it take to the floor to stop the book, and by this time...

We are performing an experiment to determine the viscosity of water using the falling sphere method. I understand that the ratio of the radius of the sphere to the radius of the container has to be within a certain range in order to avoid a false high viscosity value. And a correction factor is...

Homework Statement Grains of sand of mass 3.10 10-3 g each, fall from a height of 0.8 m on a sticky surface at a rate of 50 grains per second per cm^2. What pressure does this shower of sand exert on the surface, assuming that air resistance can be neglected? Homework Equations P=F/A...

In an attempt to teach myself rigid body kinematics I'm trying to model the trajectory of a torpedo falling through air using Matlab. I encountered somewhat strange results from a full 6-DOF parametrization, and consequently reduced the problem to a 3-DOF parametrization using only horizontal...

Homework Statement Derive an equation that relates the velocity of a freely falling particle to its altitude. Assume that the particle is released from rest at an altitude from the Earth's surface. Express your answer in terms of the variables and , constant gravitational acceleration at...

Homework Statement In a closed isolated system, a small rigid ball is held at height h1, which we will call state A. By remote control a pin is pulled and the ball is released. It falls to height h2, called state B. Calculate the change of entropy S of the system. Is it a reversible or...

A stone falls from the high bridge and reaches the ground in 10 sec, then height of bridge is approximately __________ (a) 590m (b) 460m (c) 500m (d) 1000m the object falling has an acceleration due to gravity of 9.8m/s^2 and it reaches the ground in 10 secs so the using the formula...

Homework Statement A point mass m falls from rest through a height h. The frictional force is given by -\gamma \dot{z} and gravity by -mg. Give the 'equation of motion' (differential equation) for the height z(t).The Attempt at a Solution \ddot{z} = -g - \frac{\gamma}{m} \dot{z} I thought...

[PLAIN]http://img600.imageshack.us/img600/1236/kinema.jpg Focusing on the plane first: When the package is let go, it has a Vy of V, no acceleration, so y=Vy*t In the z direction: a=-g Vz=-gt z=.5H-.5gt^2 In the x direction: x=0 Now for the ship: Given is Vs=Vx=U-at...

A Physics book, mass unknown, is dropped 4.50m. What speed does the book have just before it hits the ground?

OK, so this is what I read: << Moderator added link for attrubution >> http://education.jlab.org/qa/gravity_01.html Here's what I'm confused about. Let's say there is an object that weighs a ton on Earth's surface and a replica of that object in orbit at the distance where it weighs...

Homework Statement For a spherical celestial object of radius R, the acceleration due to gravity g at a distance x from the center of the object is g = (g0)(R^2)/(x^2), where g0 is the acceleration due to gravity at the object's surface and x > R. For the moon, take g0 = 1.63 m/s2 and R =...

I'm a little confused about what an observer would see while watching something fall into a black hole. From what I've read, an observer would see the object appear to move slower as it approaches the event horizon, due to time dilation, and it woud take an infinite amount of time to reach the...

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=...

Homework Statement An upright standing rod of mass m and length 2l receives a small push at the top and falls. The floor is smooth. the height of the center of mass at any given time is h, according to the drawing. Show that the velocity of it's center of mass is...

I don't understand this, potential gravitation says that if i drop a rock it's energy is converted into kinetic energy of motion as it falls, so that the higher up it is released the more energy it has kinetically when it hits the ground, both balance out the potential and kinetic energy so that...

We would most likely grow in temperature greatly correct? I know this sounds to basic but the answer would help me very much. Because if our body absorbs all of the visible spectrum except the part it reflects, why don't we grow very high in temperature?

If I have a box 1m deep by 2m high weighing 50kg and then bold another box onto it at one end that is 0.275m deep by 2.5m high weighing 100kg. Assuming each objects centre of gravity is central. At what angle would I need to lift the larger box to so pivoting on the smaller boxes corner...

Homework Statement There is a stick of length l moving at velocity v to the right on a table of height h. Calculate the time and angle at which it loses contact with the table from the point where exactly half of the stick is off the table. Homework Equations F=ma x=wt+1/2at^2...

Homework Statement 1) a circuit is composed of a square wire of side length l, mass m, resistance R and thermical capacity c. It is placed on the xz plane, with corners at the points (0,0), (0,l), (l,0), (l,l). The magnetic field is 0 for positive values of z, aligned along the y-axis and...

First of all, I apologize if this is the wrong forum... I couldn't tell real well where I should post it, so I just did it in general... If it's the wrong place, I apologize and request it be moved to where it should go. (I don't think it's qualifies as Homework", as it's not homework... I'd...

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...

Homework Statement A tree is cut with a 45 degree wedge to the center of the tree. The height from the base of the wedge to the top of the tree is 50 feet. The weight of the wood from the base of the wedge to the top of the tree is 500kg. Assuming there is no resistance when the tree starts...

Has anyone ever considered this issue with magnet falling in copper tube?? Homework Statement I must explain why a magnet falling in a copper tube slows down. Homework Equations F = B^qv However, I must *explain* this, I don't have to calculate anything The Attempt at a Solution...

Homework Statement A thin semicircular conducting ring of radius R is falling with its plane vertical in a horizontal magnetic field B (see fig). At the position MNQ, speed of the ring is v and the potential difference developed across the ring is - (options are given)The Attempt at a Solution...

can someone help me with this. you have a free falling weight such as a 500 lb. steel ball dropping from 3 ft. How much force will the weight produce in ft. lbs. or tons when hitting the ground. what is the formula for figuring this. Also, will the amount of force double if dropped from 6 ft...

1. A 2kg bucket of water is attached to a 1.5m long string and swung in a vertical circle with a constant speed of 12 m/s. What is the minimum speed the bucket can be swung at while still retaining the water. 2. The bucket has a maximum tension force on the string at the bottom, with 212 N...

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 =...

Homework Statement A meter stick stands on a frictionless surface and leans against a frictionless wall as shown. It is released to fall when it makes an angle of 1 degree from the vertical. Use Lagrange and Euler to find how long it takes the stick to fall to the ground. The Attempt...

Homework Statement A ball falls from the top of a building. It falls past a window. It is in view for .16 seconds. The window is 1.7 m long. How high was the building off which it was dropped? Homework Equations I'm trying to use .5 a t^2 + vt + x but it's not working The...

Homework Statement With what power we should force the body with mass 5 kg to make it fall down vertically with acceleration 15 m/s²? a = 15 m/s² g = 10 m/s² m = 5 kg; F - ? Homework Equations F = m×a; F = m×g; The Attempt at a Solution F = m × (g + a); But this is not right...

Homework Statement If the original height of a falling rock is y1 = h = 3.0m; calculate the rock's speed just before it hits ground.Homework Equations From conservation of mechanical energy law 1/2mv1^2 + mgy1 = 1/2mv2^2 + mgy2 The Attempt at a Solution I think I'm supposed to find v2 i.e...

Hi, I need to calculate an estimate of the reflected electron beam power in the form of back scattered electrons and secondary electron emissions from a tungsten/Graphite target. The Electron source is a 25kV source with operated at a power of around 25kW. The tungsten. graphite blocks are...

Homework Statement The multiflash photograph in Figure A shows two balls falling from rest. The vertical rulers are marked in centimeters. Use the equation s=490t^2 (the free-fall equation for s in centimeters and t in seconds) to answer the following questions: a) How long did it take the...

Homework Statement A 1.80 m long thing rod is balanced vertically on its tip on the floor. It starts to fall and its lower end does not slip. What is its angular speed just before it hits the floor? Homework Equations 1/3ML^2 L=mvr The Attempt at a Solution When I first started...

Homework Statement A glass sphere of diameter 1.75 cm and density 2.5 g/cm^3 falls through water with a terminal velocity of 0.3m/s. A wooden sphere of the same diameter and density 0.85 g/cm^3 is released from the bottom of a tank of water. Determine the terminal velocity with which the...

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...

I have a question regarding the terminal velocity of an object falling through a liquid. Now the speed will increase up to the terminal veloity in a given time. What I do not understand is in this calculation I'm performing (solving the equation of motion for the speed, when acceleration equals...

Hi I am trying to solve this problem. I already got the answer but have some questions. A long uniform rod of length L and mass M is pivoted about a horizontal, frictionless pin through one end. The rod is released from rest in a vertical position, as shown in Figure P10.61. At the...

Homework Statement A wire hoop is placed in front of a strong magnet, with the magnetic field B=1.1 T, pointing as shown. The strength and direction of the magnetic field are constant through the loop. The sides of the hoop have a track in which a copper wire of length 9.1 cm and mass 25 g, is...

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...

When a body falls from a height (h) under gravity,the work involved is mgh. How do you describe this work? Is it 'work done by the force (gravity) on the body' or 'work done by the body'. The confusion is, if work is done on the body the body gains energy; but if work is done by the body the...

Homework Statement A satellite in a circular orbit around the Earth with a radius 1.021 times the mean radius of the Earth is hit by an incoming meteorite. A large fragment (m = 65 kg) is ejected in the backwards direction so that it is stationary with respect to the Earth and falls directly...

A rocket shoots upward with a velocity of 500 feet/sec. Neglecting air resistance, how high will it travel? Is that even enough info to solve the problem? I don't remember how to solve that.

Einstein's equivalence principle states that free-falling observers are in local inertial frame, so one can construct a local Minkowski frame everywhere. So my question is whether the logic can be inversed, does every local Minkowski space represent free-falling? because in vierbein...

If an average adult male fell from a bridge (ex. golden gate) what would be the impact on his body when he hit still water versus water with waves. What is his acceleration, momentum, and his change of momentum when he hits the water With these in mind how does the fall affect his organs...

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...

Hi, in this thread I want to discuss some problem that I wonder. I'm interested in "Probablilty" The first wondering is How can I express that probability follow an exponential. I'm wonder why probability expess in exponential? and Can I show it, if I experiment something, that graph...

Homework Statement Two spheres of mass M1 and M2 are arranged one above the other as shown. They are separated by a fraction of a mm. They are released from rest and allowed to fall to the ground, a distance h = 6.5 m below. Mass M2 collides elastically with the ground and then elastically...