Free fall Definition and 486 Threads

I posted this problem in another section, but it seems to have fizzled out and I’m trying to solve it, so resurrected it here hopefully to get somewhere. I’m trying to calculate the impact force of a free falling cylinder of metal under water accounting for the drag. The cylinder is...

Homework Statement [/b] Problem: How much Air Resistance acts on a 100-N bag of nails that falls at its teminal speed? What process do you use to solve this?

[b] an elevator car weighing 50,000 N is 27m from the ground. the cable snaps and the elevator goes into free fall. Shock absorbers have been provided, the coil length is 1 m. Assume elevator is able to lock onto the shaft at the point of contact w/ the absorber so that it does not bounce...

Here is the original question: - Well, the answer that I came up with is, that, since there is no eternal force on the system, the centre of mass cannot be displaced, no matter what. Now, my doubts are regarding this itself. When the ice melts, it turns into water of lesser volume. In the...

I'm reading a maths book called Thomas Calculus and in their method for getting the average speed of an object when only the height its dropped from is known is this formula here which they call Galileos law: y = 16t^2 y being the distance traveled after time. What I don't get is where they...

I would appreciate any insight into these questions; I have had a little EM but no general relativity. Maybe general relativity is not involved at all - just EM with an observer in an accelerated frame. 1. Suppose we have two charged particles Q1 and Q2. Q1 is sitting on our lab table. Q2...

Homework Statement An object is launched upwards with a velocity of 25 m/s. At what time (or times) will the object be located twenty meters above the ground? Homework Equations The Attempt at a Solution I started off with the following variable list: Xo=0 Vo=25 X=0 V=0...

Homework Statement A rocket is fired vertically and ascends with a constant vertical acceleration of 20.0 m/s^2 for 2.00 seconds. Its fuel is then used up and it continues as a free object. What is the maximum altitude reached? Homework Equations X=Xo+Vot+(1/2)at^2 V=Vo+at...

Homework Statement A jumbo jet needs to reach a speed of 300 km/hr on a runway for take off. Assuming a constant acceleration and a runway 2 km long, what minimum acceleration from rest is required to get the jet in the air?Homework Equations I tried using the equation: 2a(X-Xo)=V^2+Vo^2 But...

1. Homework Statement A package is dropped from a helicopter. Note that both the helicopter and package are traveling upward at 10.0m/s when the package is released. If the package takes 3.5 seconds to hit the ground, how high was the helicopter when the package was released? If the...

I've seen this equation in a book once but I can't seem to find a good explanation of how it was derived. \ t_{ff}=\sqrt{\frac{3\pi}{32g\overline{\rho}}}

I recently read an article about Joseph Kittinger which stated that in a skydive, he was subjected to a G force of 22 m/s^2. Disregarding fluid resistance, don't objects in free fall always experience one g?

Homework Statement Rachel drops straight off a high dive whose board is 5 meters above the surface of the water. How long does it take Rachel to hit the surface of the water? How fast is Rachel traveling when she hits the surface of the water? Homework Equations The Attempt at a...

Homework Statement A package is dropped from a helicopter. Note that both the helicopter and package are traveling upward at 10.0m/s when the package is released. If the package takes 3.5 seconds to hit the ground, how high was the helicopter when the package was released? If the helicopter's...

Hi everybody, I am trying to find an analytical solution of the equation of a falling particle of mass M in a gravitational field (described by constant K) when the gravity depends on distance, as in Newton classical theory(I simplified in one dimension). The equation could be M*d2 X(t)/ dt2 =...

Homework Statement Figure out the height of the building using free fall formulas and only knowing two times: 3.25 second acceleration, 1.25 seconds decceleration. Find the height.Homework Equations Dy=V0t + 1/2at2 (only one I can think of that applies)The Attempt at a Solution Dy=V0t +...

Homework Statement If a car rolls gently (v0 = 0) off a vertical cliff, how long does it take it to reach 73 km/h? A helicopter is ascending vertically with a speed of 7.50 m/s. At a height of 110 m above the Earth, a package is dropped from a window. How much time does it take for the...

Homework Statement a stone is dropped into th water fro a bridge 44 m above the water. another stone is thrown vertically 1.0s after the first is dropped. Both stones strike the water at the same time. What is the initial speed of the second stone? Homework Equations x = x0 + vx0t...

So i have two questions i need help answering. its not homework, but its from a previous exam my teacher gave. x0=x knot and v0= v knot Homework Statement a rock dropped from a cliff falls one-third of its total distance to the ground in the last second of its fall. determine the height of...

hello, consider a man falling from a roof with a heavy box in his hands. what should he do with the box?

Homework Statement It's a two part question, but it basically says this: a bolt drops from an elevator 9.0 ft from the ground, at what time does it hit the ground? Homework Equations x = x0 + vx0t + 1/2ax(t^2) The Attempt at a Solution since it's a free fall question and...

Homework Statement A person jumps from the roof of a house 4.4 m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70 m. The mass of his torso (excluding legs) is 40 kg. (a) Find his velocity just before his feet...

Homework Statement A ball moving with constant speed 1.0 m/s on a horizontal table rolls off the edge of the table. The ball hits the floor 0.50 seconds after leaving the edge. Suppose you roll the same ball on the same table with constant speed 2.0 m/s. After leaving the edge of the table...

Homework Statement A bolt comes loose from the bottom of an elevator when it is at a height of 15 m above the bottom of the elevator shaft. If the elevator is originally moving upward at a speed of 7.5 m/sec, assuming that the elevator continues to ascend at a constant speed, how high above...

This question has bothered me for few weeks: Lets say I was at some height above a super massive planet that has no atmosphere (i.e. no air resistance. If I were to begin falling what would stop me from being accelerated by the gravitational field of this planet to the speed of light? Assume...

Homework Statement http://i214.photobucket.com/albums/cc4/twinkie34005/untitled-10.jpg http://i214.photobucket.com/albums/cc4/twinkie34005/untitled-11.jpg Free fall problems, help please Homework Equations V = vi + a*t = .9+9.8*3.2 = 32.26 m/s Y = vi*t + ½gt² = 53.056 m...

Homework Statement It is desired to have a pile driver strike a pile with a speed of 20 m/s. Assuming the driver to be in free fall, from how high above the pile should be released? Homework Equations Used v^(2) = V(o)^(2) + 2ax v=final velocity V(o) =initial velocity a=acceleration...

Homework Statement During launches, rockets often discard unneeded parts. A certain rocket starts from rest on the launch pad and accelerates upward at a steady 3.30 m/s^2. When it is 235 m above the launch pad, is discards a used fuel canister by simply disconnecting it. Once it is...

can someone please help me?? I thought I had the answer to this problem, but it doesn't match the book's answer. I can't figure out what I'm doing wrong. This is the problem: A rocket is launched straight up with constant acceleration. 4 seconds after liftoff, a bolt falls off the rocket and...

Homework Statement A student drops a ball from the top of a tall building; it takes 2.5 s for the ball to reach the ground. A.What was the ball’s speed just before hitting the ground? B.What is the height of the building? Homework Equations v=V(not) + at x=V(not)t + 1/2at(Squared)...

Homework Statement A mass m is dropped from a height H onto a hard, flat surface. When it collides with the surface, it rebounds with the same speed it had before the collision. However, there is a constant force of air resistance f acting on the mass as it undergoes this motion. Answer the...

Homework Statement Two students are on a balcony 23.5 m above the street. One student throws a ball, b1, vertically downward at 14.1 m/s. At the same instant, the other student throws a ball, b2, vertically upward at the same speed. The second ball just misses the balcony on the way down...

A model rocket with a mass of 0.50 kg is fired vertically from the ground. Assume that it is streamlined enough that air resistance can be ignored. Suppose it ascends under the influence of a constant net force of 2.0 N acting in a vertical direction and travels for 6.0 s before its fuel is...

My mechanics book says that if a rock falls freely to Earth from a certain height than it will be deflected slightly to the east due to the Coriolis force. But I don't understand why. Consider the following Wikipedia picture: If we imagine that we're looking at the nothern hemisphere from...

I might sound like an idiot asking this question, but, how does a body have zero weight in free fall??

Homework Statement An object falls from height h from rest. If it travels .50h in the last 1.00 s, find (a) the time and (b) the height of its fall. Explain the physically unacceptable solution of the quadratic equation in t that you obtain. Homework Equations Pretty much any free...

Homework Statement A rocket is launched to travel vertically upward with a constant velocity of say...20 m/s.After travelling maybe 35 s the rocket develops snag and its fuel supply is cut off. the rocket then travels like a free body, the height achieved by the rocket will be...

Homework Statement 1)A 3.0kg chair at rest is pulled across the floor by a 20N force.If the co-efficient of friction between the floor and chair is 0.25, calculate: a)the net force on the chair. answer=13N b)the displacement of the chair after 2.0sm answer=8.4m...

Homework Statement A small first-aid kit is dropped by a rock climber who is descending steadily at 1.2 m/s. a) After 4.2 s, what is the velocity of the first-aid kit? Answer in units of m/s. Ok i know that the velocity after the 4.2 sec is -42.36 however the question asks how far is the...

Homework Statement Determine the value of 'g' Homework Equations AnythingThe Attempt at a Solution I only know of the pendulum method. Can someone please show me of other methods to calculate g without the use of fancy equipment such as a picoscope.

Homework Statement Need to solve the differential equation which models the velocity of a sky diver. Homework Equations dv/dt = -9.8 + 0.0045Av^2 where A is cross sectional area (assume 0.75m^2) v(0) = 0 The Attempt at a Solution ok the problem is to find v(t) as a function time. as...

Having trouble with the equation to solve the problem. A flowerpot falls from the ledge of an apartment building. A person in an apartment below, coincidentally in possession of a high-precision timing system, notices that it takes 0.20 seconds for the pot to fall past his 4.0 m high window...

Hey guys need help beginning to solve the following: A skydiver accidentally drops a camera out of the plane. The diver notices the mistake 3.0s later and dives out of the plane with a downward velocity of 10.0 m/s. The camera experiences free fall(9.8 m/s^2), but the sky diver accelerates...

Homework Statement An airplane releases a spacecraft , after 2 seconds the spacecraft s engine starts providing it with a horizontal velocity of 6m/s relative to the aircraft. What is the magnitude and direction of the velocity after 2 seconds? After 3? Assume the spacecraft is in...

Homework Statement I was given a problem to solve for the speed of a body falling under gravity [equation (1)] where g is acceleration due to gravity, which was easy enough.. but then i thought i would extend it to the case where g is non-constant, and so arrived at equation (2), (where where...

Homework Statement A rock thrown straight up climbs for 2.50 s, then falls to the ground. Neglecting air resistance, with what velocity did the rock strike the ground? Homework Equations well we are looking for v=? we have: t=2.50 s and g=9.8 ^do we need gravity? yes, right? =S...

I read about electrons and positrons free fall within a superconducting cylinder, in this book (p 105): https://www.amazon.com/dp/0521675537/?tag=pfamazon01-20 I don't understand what I read. Apparently, electrons would feel an electric field mg/e that would actually freeze them in the...

Homework Statement From the GRE 0177 practice exam: A thin uniform rod of mass M and length L is positioned vertically above an anchored frictionless pivot point, as shown above, and then allowed to fall to the ground. With what speed does the free end of the rod strike the ground? The...

Homework Statement A ball is dropped from rest from the top of a building and strikes the ground with a speed vf. From ground level, a second ball is thrown straight upward at the same instant that the first ball is dropped. The initial speed of the second ball is v0 = vf, the same speed...

Hello Homework Statement I have this problem, even though it might seem very simple. A boy falls from a distance and lands on a net. When he reaches the net, it de-accelerates him with 4*g. The question is: What amount force does the boy exert the net? The Attempt at a Solution I would say...