Free fall Definition and 486 Threads

Homework Statement Heather and Jerry are standing on a bridge 50\;m above a river. Heather throws a rock straight down with a speed of 20\;m/s. Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air resistance. How much time elapses between the...

I've tried finding this in the forums elsewhere, but can't seem to find the answer I'm looking for. So here's my dilemma... There are two objects, object X and object Z, that are the same volume and shape. However, object X has a greater mass than object Z. Objects X and Z are both dropped...

In free fall, there is no air resistance, so the only force acting upon the object of free fall would only be its weight. Now the question is, if an object keeps accelerating due to free fall, wouldn't it eventually reach the speed of light? For example, Earth's g=9.81 m/s^2, so over a course...

Homework Statement A body falls vertically from rest. During the nth second it falls a distance d. Prove that by the end of the nth second it has fallen a total distance (D) of (2d+g)^2/8g Homework Equations x = x0 + V0 + 1/2at^2 where x0 = initial position v0 = initial velocity a...

Homework Statement maria throws an apple vertically upward from a height of 1.3 meters with an initial velocity of 2.4 m/s. A) will the apple reach a friend in a treehouse 5.3 m above ground B)how long will the apple be in the air before it hits the the ground Homework Equations...

1. To determine how high a cliff is, a llama farmer drops a rock, and then 0.800 s later, throws another rock straight down at a velocity of −10.0 m/s. Both rocks land at the same time. How high is the cliff? 2. I know some kinematics equations must be used 3. I am stumped...

Homework Statement A man standing on the sidewalk throws a set of keys vertically upward to his wife in the window of their apartment 4.0 m above. The wife catches the keys 1.5 s later. (a) With what initial speed were the keys thrown? (b) What is the velocity of the keys just before they were...

Free Fall Trajectory So I am basically lost in what that means. I think it is the component method for vectors? Am I right? Some background on the lab: We rolled a marble down a curved ramp so that it went off the table and hit the ground in front of the table. (we marked where it hit with...

Homework Statement a ball is thrown straight down from the top of a 220 feet building with an initital velocity of -22ft/s. What is the velocity of the ball after 3 seconds? What is the velocity of the ball after falling 108 feet? Homework Equations s(t) = -16t^2 + Vi(t) + si...

Homework Statement A ball is dropped from 1.5 y(m) and hits the ground in .54 t(s). What is the value of g (m/s^2)? The accepted value of g = 9.8m/s^2 Homework Equations y=1/2gt^2 The Attempt at a Solution I'm getting this wrong, but this is my attempt. 1.5 = 1/2g x .54^2...

Homework Statement A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 8.20 m/s at an angle of 15.0° below the horizontal. It strikes the ground 3.00 s later. (a) How far horizontally from the base of the building does the ball strike the...

Homework Statement A stone is thrown upward at an angle of 51° above the horizontal. Its maximum height during the trajectory is 26 m. What was the stone's initial speed? m/s Homework Equations a=v2/r v2=vo2+2ax C=2\pir The Attempt at a Solution I figured the acceleration is...

A doctor, preparing to give a patient an injection, squirts a small amount of liquid straight upward from a syringe. If the liquid emerges with a speed of 1.5 m/s how long does it take for it to return to the level of the syringe? what is the maximum height of the liquid above the syringe...

Hello friends, I am very new to this forum and I´d like to consult you if i have any questions. Currently I am studying basic physics for my ug. I´d really apreciate it if you could help me out. Homework Statement A ball is thrown straight up from the edge of the roof of a building. A...

Sometimes Technology makes me happy, and sometimes it makes me cry, and THIS is definitely one of those times that it makes me cry. So we used a free fall program to give us values of the distance, velocity, time and acceleration. Then we had to graph it on Excel, and then find the...

1.what are the the constants of motion of a free fall body(treat this as a one-dimension motion,so there are two [independent] constants of motion )? 2.are they initial velocity and initial displacement？ 3.and i know the total energy(T+V) is one,but they are not independent with the...

Homework Statement 45. A freely falling object requires 1.50 s to travel the last 30.0 m before it hits the ground. From what height above the ground did it fall? Homework Equations x = xi + Vit + (1/2)at2 Vf2 = Vi2 + 2ad The Attempt at a Solution First found the initial...

HELP! PLEASE concepts in free fall an object is thrown upwards, at the top of the path it has a) zero acceleration b) maximum momentum c) maximum kE d) is at equillibrium e)none of the above i know accelarion is 9.8m/s^2 i also know is not KE since at the top is potential im...

The moon's gravity is about one sixth of the Earth's. (Basically, one sixth of 9.80m/s^2). If two objects were dropped at the same height on the Earth and on the Moon, the time it would take for the object to reach the surface of the moon compared to the Earth is... a) 6 b) 36 c) Square root...

Hi everyone! I have 7 questions here, I completed them all, but I’m not sure if I got them correct. I would greatly appreciate it if someone could have a look at them and let me know if I need to fix anything - I had the most trouble with question 3. Thank you so much for your time! :smile...

A flea jumps straight up to 0.390m. How long does it stay in the air from the time it jumps up to the time it lands? First of all, I found the initial velocity. with the initial velocity, i tried using the equation d = v1t + 1/2at^2 to get the time. but apparently it's wrong...;; How do...

Homework Statement an attacker at the base of a castle wall 3.65 m high throws a rock straight up with the speed 7.40 m/s at a height of 1.55 m above the ground. a.) will the rock reach the top of the wall? b.) if so, what is its speed at the top? if not, what initial speed must it have to...

Hi, Some time back I was saw a discovery documentary, can't remember the name, but in that somewhere they told that under free fall if possible to centre of earth, it will take around 32 Hrs or so.. No calculations or details were given. So I wonder will it take so much time or how...

A freely falling object requires 1.50 s to travel the last 30.0 m before it hits the ground. From what height above the ground did it fall? I have been working on this for a while and seem to be going wrong somewhere. I am unclear as to how free fall is meant here. I know that it need...

I am having trouble with this one. for all the formulas I tried I need the velocity, which they don't tell us in the problem. Any help would be appreciated . A stone falls from rest from the top of a cliff. A second stone is thrown downward from the same height 2.4 s later with an initial...

Homework Statement A wrecking ball is hanging at rest from a crane when suddenly the cable breaks. The time it taktes for the ball to fall halfway to the ground is 1.2s. Find the time it takes for the ball to fall from rest all the way to the ground Homework Equations v=vo + at The...

AP free fall question (solved) Homework Statement I have problem with question b. A hot air bolloon is traveluing vertically upward at a constant speed of 5.00m/s. When it is 21.0m above the ground, a package is released from the balloon. a) for how long after being released is the...

Homework Statement Suppose you adjust your garden hose nozzle for a hard stream of water. You point the nozzle vertically upward at a height of 1.5 meters above the ground. When you quickly move the nozzle away from the vertical, you hear the water striking the ground next to you for another...

Homework Statement Falls resulting in hip fractures are a major cause of injury and even death to the elderly. Typically, the hip’s speed at impact is about 2.0 m/s. If this can be reduced to 1.3 m/s or less, the hip will usually not fracture. One way to do this is by wearing elastic hip pads...

A ball is thrown upward with speed V. At the instant the ball is thrown, second ball is dropped from rest at a height H above the thrown ball, but not directly above it. Ignore air resistance. How much time elapses before the balls pass each other? Find a value of H such that the ball thrown...

Homework Statement A student at a window on the second floor of a dorm sees his math professor walking on the sidewalk beside the building. He drops a water balloon from 18.0 m above the ground when the prof is 1.00 m from the point directly beneath the window. The professor is 170 cm tall...

Homework Statement A brick falls from the top of a building and drops past a 2.0 m tall window in 0.20 s. Determine the distance between the top of this window and the top of the building. Homework Equations v^2 = (v initial)^2 + 2ax The Attempt at a Solution 10 ^2 = 2(9.8)x...

1. 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 1.2 seconds. Find the time it takes for the ball to fall from rest all the way to ground 2. Vf=Vo-gt, Vf^2=Vo^2-2g(delta y), Yf=Yo+Vot-1/2gt^2 3. I...

Homework Statement Aristotle believed that the time it takes for an object to fall a given distance is inversely proportional to its weight. Given objects A,B,C and D with weights of 10,40,20 and 30 grams, which one would have the heights terminal velocity if dropped from the same height...

A ball is shot out from a point A with initial velocity v. If it goes 55 meters in 4.4 seconds before it lands, what was the initial velocity and in what direction was the ball kicked? I first find the initial velocity in x-direction: 12.5 m/s. Then I use energy conservation in z-direction...

Foster and Nightingale give an equation for the proper time of a radially falling clock between any two distances. (Short Course in General Relativity, 1979, p. 128.) As they state, the equation is the "same as its Newtonian counterpart." So there are no factors representing any slowing of the...

Hello. Why is it so that the accelaration of free fall on a unit mass on equator = Gravitational force -Centripetel Force? Answer ample for a level purposes is required...

Homework Statement A starship is circling a distant planet of radius R. The astronauts find that the free fall acceleration of their altitude is is half the value at the surface of the planet. How far above the surface are they orbiting? The answer should be a multiple of R. Homework...

Homework Statement A lead ball is dropped into a lake from a diving board 5.44 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 4.84 s after it is dropped. (Assume the positive direction is...

Homework Statement A ball rolls off an incline plane on top of a 1m high table and strikes the floor 62.5cm from the edge of the table. What was the velocity of the ball just as it left the incline plane? The incline is given as 30 degrees. I've put my frame of reference at the point where...

I am not very good at this so please help me someone. I am not sure if I am in the right forum or not but i can almost put money on you guys know these simple questions. 1. Which of the following statements applies to the motion of a ball rising and then falling in free fall? I. The...

[SOLVED] Free fall far away from Earth (integral substitution problem) Homework Statement Given: v(x) = -v_1\sqrt{\left(\frac{R}{x} - \frac{R}{h}\right)} Find the time t. Homework Equations Listed above where v_1 , R , h are all constant. The Attempt at a Solution v(x) =...

Problem: An egg is thrown downwards at 2 m/s from the top of a bridge. At the same moment, a fisherman standing in a stream 30 m beneath the bridge throws a rock upwards at 15 m/s. How fast will the stone be moving when it and the egg are at the same height above the water? This...

A ball of mass .5 kg is dropped from a height of 5 m. What is the greatest velocity it will have just before hitting the ground? vf squared = vi squared + 2ad vf squared = 0 squared + 2(9.8)(5) vf = 9.8 m/s So the greatest velocity is 9.8 m/s, right? I am still very confuzzled and I think...

Hey guys, when an object is free falling, is it still under the effects of air resistance? If it was not under the effects (an environment without air resistance) is free fall possible? (I am looking for an argument that it is under the effects of free fall but all replies will be taken into...

This free fall problem seems simple, but I can't get it. you have a rocket fired from rest with an acceleration of 40 m/s^2. It runs for 2.5 and then falls. I'm wanting to find the maximum height, which I think would require me getting the initial velocity first. v = v0 + at 0 = v0 + 40(2.5)...

A particle is launched vertically at an upward velocity of 39.24m/s. Neglecting air resistance what is the paricle's velocity on impact average acceleration average velocity and displacement after impact

[SOLVED] *****Another free fall challange!***** A lead ball is dropped into a lake from a diving board 5.06 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 4.92 s after it is dropped. (Assume the...

[SOLVED] Challenging problem (free fall) I am stuck with couple of problems and i keep getting the wrong answer. Perhaps my approach is wrong. Below are the questions and they way i approached the problems. A basketball player grabbing a rebound jumps 80 cm vertically. (a) How much...

[SOLVED] free fall motion Homework Statement A helicopter carrying Dr. Evil takes off with a constant upward acceleration of 5.0m/s^2. Secret agent Austin Powers jumps on just as the helicopter lifts off the ground. After the two men struggle for 10.0s , Powers shuts off the engine and...