Deceleration Definition and 229 Threads

Recently, I spent some time trying to get an intuitive understanding of special relativity. (I am not a physicist, only took a few physics lectures in the mid-90s) It all went well until I tried to imagine accelerating objects with non-zero length. Specifically, I tried to imagine what a...

Phew; back n forth on this anyway, my lines ... ##v_{1} = \dfrac{1000}{20} = 50## m/s in the first ##10## seconds. ##v_{2} = \dfrac{1000}{30} = \dfrac{100}{3} ##m/s in the first ##35## seconds. where ##v_1## and ##v_2## are the respective velocities in ##10s## and ##35s## respectively...

I think, since the train is decelerate the kid will fall off at free falling. the time for that is: y=0.5*9.8*t2 ⇒ t=√(2*y/g)=√(2*3/9.8)=0.8sec. Now i think i need to find what is the distance the train is doing in this time, but i can't figure this out.

I tried the formula I showed up there but got 0.399 instead of 7.88rad/s^2.

365 rotations - 365 days 365 days - 31536000 s apart from that I do not know how to continue the question

6.0 rev - 1 s 1 rev - 1/6 5.0 rev - (1/6) x 5 = (5/6) s = 0.833 s I do not know how to calculate the angular acceleration

So I get the exercise and all and have just solved it. But .. I kind of very very intuitively determined ##\theta## to also be the angle for the circular sector. The problem here is that my geometry bag is very weak, I didn't have any geometry in HS, will fix that sooner or later but anyway...

Wawawawawawa! This was a tough one...:biggrin: Find the question below; Find my approach below: We have the following equations; 1. ##v=30-0.5t## 2. ##v=30-1.5t## Now the car changes its acceleration at some point i.e from ##-\frac{1}{2}## ##m/s^2## to ##-\frac{3}{2}## ##m/s^2## ... I...

Basically the problem is giving me an initial velocity to start with it goes up the incline before it comes back down. I know how to do everything else in the problem but solve for the initial acceleration up the incline. What would I need to calculate to solve this?

My approach so far is to use F = ma. The forces acting on the block in the horizonital direction are friction and the force of the spring. Choosing the direction towards the spring as the positive axis. Therefore: F = ma -Fr - kx = ma Solving for a = (-Fr - kx)/m If I plug in values I end up...

For this question, I don’t understand the steps for the relative motion part. When I try it I get angular acceleration to be zero which is obviously wrong. The solution doesn’t consider the Y distance between G and A but I don’t understand why. In the relative motion equation it’s suppose to be...

I am a junior engineer tasked with modeling the dynamics of a small research UAV after landing. The UAV has 3 tires, 1 on the nose landing gear and 2 on the rear landing gear. The rear tires are equipped with disc brake calipers. My coworker has explained that the simplified model (MODEL 1...

Hi, Hope this is the correct forum for this kind of question. I am doing an explicit finite elements simulation of a tank, weighs around 7.5 Kg with internal parts, falls from 1 meter. Since I never had a validation of such an experiment I am trying to understand if the numbers are right. I...

So my work includes using the acceleration formula a=delta v/t (Vrtf-Vrti)/a -> (0-54)/(-0.31) -> t=174 seconds I plug in 174 seconds to find the acceleration of the left train. and got -0.22m/s^2 I then used the displacement equation x=(1/2)at^2+Vo+So coming out with Xrt=4703m and Xlt=...

i have no idea how did the answer come in conclusion...i guess that cosθ and sinθ is referring to the 2 dimensions of the acceleration ? but how? and why?

Hey all, I need a reality check and verification on some work I have been doing. I feel as though I might be too close to the problem now and am missing something about this. It's also been a few years since I studied physics at University, so I'm a little rusty. Problem: An initially...

I note the general Taylor series for ##a(t)## as: \begin{equation} \begin{split} a(t)&\approx a(t_0) + a'(t_0) (t-t_0) + \frac{1}{2!} a''(t_0) (t-t_0)^2 ... \end{split} \end{equation} which I rewrite as: \begin{equation} \begin{split} a(t)&\approx a(t_0)\left(1 +...

I have a question about this picture: It shows matter traveling at relativistic velocities away from a black hole: "Figure 5.21: This VLA image of the radio-loud quasar 3C 175 shows the core, an apparently one-sided jet, and two radio lobes with hot spots of comparable flux densities. The jet...

Problem Statement: A known mass at a know velocity collides on a spring of known stiffness. What is the equation that governs the deceleration of the mass, so that the force on the spring could be found? Relevant Equations: 1/2 m*V^2 = 1/2*k*x^2 + 1/2*m*(Vo)^2 Kinetic energy of mass before...

Note: Maths has always been kinda a weak point for me in school. Anyway. From hereon I'm going to talk about this in the context of a train for simplicity, even though this is actually needed for an entirely different context - but I don't think this is relevant for the problem. In terms of my...

Hi, i have one big problem with this simple formula, i tried many ways and combinations, but nothing worked how i wanted it. Let's assume we have a distance, let's say it's 100000 units of any type, could be virtual since i am trying to program a 3d physics engine. The object pass that...

Homework Statement Homework Equations modified Freidmann: The Attempt at a Solution for part b) I am not sure what to do as I am not sure what they mean by and

Hi Folks, I am a private tutor and one thing I teach is A level Physics (OCR Physics A). Am I the only person who has been sometimes baffled and deeply disappointed with some of the questions/answers? Let me explain what I mean. I see questions form which it's not possible to decide what kind...

Homework Statement At a given time ##t=0##, a car 1 moving with constant velocity ##v_{1}## breaks with constant deceleration ##d##. Another car 2 at a distance ##L## behind car 1 and traveling with constant acceleration ##a_{2}## and velocity ##v_{2}## at ##t=0## brakes immediately as soon as...

Hello I'd like to demonstrate to students how a magnet is slowed when falling through a copper pipe due to generation of magnetic force. What type of magnet should I use? ShouId it be cylindrical or flat? Which way shouId it be magnetized? I have 3/4 inch pipe. Thanks ham1

Homework Statement Compare the deceleration of the squirrel to airmen. The squirrels velocity being 7.67 (m/s) ignore air resistance, stopping distance of 3.9 cm, deceleration of an airman being 486 (m/s^2), velocity being 54 (m/s) and stopping distance of 3.0 m. Homework EquationsThe Attempt...

Hi, i am trying to understand, how to calculate the deceleration of the object? I have a small toy car in the track, after i release the car, i want to calculate the deceleration of the car, and predict how many loops, it's going to do, after measuring the timing of some revolutions. Is there...

Good day, I have a question regarding calculating the total reached height ##H## of an object that is thrown upwards with an initial velocity ##v_i##, while taking into account the decreasing gravitational deceleration ##g## with height as well.The formula would be something like: $$v_i \cdot t...

I am doing this as a hobby, trying to understanding some physics calculation for camshafts and following cam s,v,a,j. All pictures in this thread are just samples that tie to nothing much, other than just images. 1. From the 1st image above, the camshaft (emulated digital signal) is...

Homework Statement A boat, moving at the velocity of 9,9m/s turns off its engine and starts decelerating at the rate of a=-kv^2. What is the velocity of the boat after 4,9 seconds if the constant k is k=5,5m Homework EquationsThe Attempt at a Solution I tried to integrate deceleration to get...

Hi! I have this homework problem that has me completely stumped. Any help is greatly appreciated! In coming to a stop, a car leaves skid marks 80m long on the highway. Assuming a deceleration of 7.00m/s2, estimate the speed of the car just before braking. I just can't figure out what formula...

Homework Statement Captain American bails out of an airplane and falls 50 meters without friction. When the parachute opens, he decelerate at 2.0m/s2. He reaches the ground with a speed of 3.0 meters/sec. a.) How long is captain america in the air? do= d= vo= v=3m/s t= ? a= -9.8m/s2 ?? (this...

ince f=ma, and we derive whatever the force it takes to accelerate a specific mass at a specific acceleration as a unit of force. I understand this ratio of actual force will always be the same in the entire universe but is there a reason why for example 1kg accelerated a 1m/s^2=1 N which is...

Hi All, In a fidget spinner. Disregarding what force applied and spinner decelerate (a) at a given time (t), at what distance (s) it travel before full stop?

Homework Statement Calculate the deceleration of a snowboarder going up a 5.0° slope, assuming the coefficient of friction for waxed wood on wet snow ( = 0.1). Homework Equations F = ma W = mg Fs = (Fn) Fk = k (Fn) The Attempt at a Solution Answer key says it's 1.83 m/s2. I fiddled...

Homework Statement The question didn't fit there. *A boy drops a metal ball from rest on sand. It hits the sand bed in one second and makes an impression of maximum depth 8mm in the sand. What is the average deceleration of the ball as it hits the sand? Assume air resistance is negligible. vi=...

Homework Statement On a particularly hot day at the racetrack, Dale Earnhardt's famous no. 88 Chevy impala (m = 1600 kg ) speeding at 200 mph (89 m/s) blows a gasket and the engine begins to deaccelerate. The car is shifted to neutral and coasts toward the pit lane. Neglecting all sources of...

After talking to a coworker, I looked into the wikipedia article on "Gravity of Earth". I found that the Earth's gravity is not uniform, which makes sense (never thought about it). I have always wondered why satellites de-orbit over time. Someone told me that there is enough space dust to slow...

I'm wondering how to calculate the force exerted on a skydiver as they decelerate from their terminal velocity of approximately 120 mph to approximately 30 mph in the course of one second, as I have seen and felt while skydiving. Thank you all in advance.

Homework Statement :[/B] A person drives a car for 20 seconds in a straight line with an initial velocity of 20m/s. During the entire course of the journey they applied breaks causing the car to decelerate at 5m/s2. How far will it be from the starting point after the given time? Homework...

Firstly I must say if this is in a wrong sub-forum I apologise. This is my first post and I'm new to the website so please bare with me. Also I was unsure of the Prefix so I again apologise if that to, was incorrect. But my Question is that is the acceleration (or deceleration) of an object...

gee i am not worthy of being here with you guys but i must know is an accelerometer's negative output due to the braking of a motor vehicle directly proportional to the the rate of deceleration of the motor vehicle and can this be predicted using a derivative function? And if I were to plot the...

Homework Statement I forgot if the deceleration is -0.003v or same here -0.003v2 Homework Equations v = u + at (first acceleration) dv/dt = a (deceleratioin) = -0.003v^2 The Attempt at a Solution From first equation, 342.2 = 0 + 30*t1 t1= 11.407s From 2nd equation, dv/v2 = -0.003...

Homework Statement If you decelerate in one direction, are you accelerating in the opposite direction? Ex. You are standing in an elevator and are slowing down, going upwards- are you accelerating downwards since you're decelerating in the opposite direction, upwards? Homework Equations -...

Homework Statement How to find deceleration of a ball that is hit, given the ball: mass=0.1kg F=20N is hit by a bat for 0.01s has an acceleration of 200ms^-2 when hit by bat speed=2m per sec travels 0.01m as it is being hit by the bat Was initially at rest.Homework Equations a=(v-u)/t The...

Homework Statement "When a high-speed passenger train traveling at 161 km/h rounds a bend, the engineer is shocked to see that a locomotive has improperly entered onto the track from a siding and is a distance D = 676 m ahead (Fig.2-29). The locomotive is moving at 29.0 km/h. The engineer of...

Homework Statement a car with an initial velocity of 10.0 m/s (W) decelerates at -2.00 m/s (s to the power of 2) (W) reaching a final velocity of 5.00 m/s (W). What is the displacement of the car? Homework Equations Δdisplacement = (final velocity to the power of 2 - initial velocity to the...

I have data from road tests done in someone else's experiment that show that a car with studded snow tires will take on average 23 meters to stop from 25 mph on packed powder at 0 degrees C. From that information, can I figure out what length of time it takes for the car to stop? Can I...

A car going 25 mph with studded tires on packed powder stops in 20 meters. What will be the stopping distance if it is going 20 mph? We do not know the mass of the car, but perhaps it is accurate to create an acceleration constant that will apply for other speeds? a=v/t and v=d/t so therefore...