Acceleration Definition and 1000 Threads

Homework Statement Hi, I have a quick question about an experiment I am doing. I did an experiment where I rolled a ball over a flat surface and dropped a ball from a height, and I was asked if the ball rolling over the flat surface (1-d) motion is subject to constant velocity? I was also...

My question is simple, in the problem on the picture that i uploaded, why is -fk =ma I understand the friction is in the negative direction, só it is negative, but the netforce, and the aceleration, are also in the negative direction ,só why are they positive? Shouldt it be -fk=-ma ?

Homework Statement Homework EquationsThe Attempt at a Solution I assume that the wheels are 8ft apart in both x and y direction. Let's denote the length and width of the car by 2l = 8 ft. The torque about an axis connected the contact points of rear wheels : ##\vec \tau = [\{l( \hat x +...

So the equation for angular acceleration on the AP physics sheet reads α = ΣT / I. I am required to prove that the units on each side are the same however I can't figure out how to get the rad/s^2 unit for angular acceleration into the same form as the right side which is N*m/ kgm^2 Any help...

Homework Statement A hot air balloon is released from the ground & rises up with a constant acceleration of 4 m/s^2. When it is 16 meters above a sandbag is dropped. What is the time taken for the sandbag to hit the ground? Homework Equations v^2=u^2+2as v=u+atThe Attempt at a Solution...

Homework Statement While strolling downtown on a Saturday afternoon you stumble across an old car show. As you are walking along an alley toward a main street, you glimpse a particularly stylish Alpha Romero pass by. Tall buildings on either side of the alley obscure your view, so you see the...

There's a common example to explain time dilation that states ... "if you traveled at a speed close to the speed of light and came back in a round trip of 1 hour , you may find that on the departure frame of reference 2 hours had passed" but that 2 hours trip can't be done without accelerating...

Homework Statement A power plant operator on a bicycle is pedaling at uniform acceleration of "a", when his initial velocity "u" m/s. After 6.2s, and 9.3s, the bicycle had moved 23.5m & 39.7m respectively. Find the value of "u" & "a". Homework Equations s=ut+1/2at^2The Attempt at a Solution...

speed = distance/time v=s/t Acceleration = dv/dt = -s/t^2 ?

Homework Statement A flywheel turns through 40 rev as it slows from an angular speed of 1.5 rad/s to a stop. (a) Assuming a constant angular acceleration, find the time for it to come to rest. (b) What is its angular acceleration? (c) How much time is required for it to complete the first 20 of...

Hello, I'm working on a (private) Software Project and Part of that is finding a Way to Predict Projectile Positions. My thought's are explained from a Code View a little bit, but I tried to clarify everything so everyone could understand what's going on. (It's my first time in this Forum, I...

Something about collisions has been bothering me. Let's say I have 2 particles with equal mass: one is moving at velocity v towards the other particle. Kinetic energy and momentum is conserved during this collision. However, I have a question: what is the acceleration of the particles during the...

Homework Statement A pulley hangs of mass, m, and radius, R, hangs from the ceiling. Two blocks of masses, m1 and m2 are connected by a massless, non-stretchable rope on the pulley (assume no slipping). What is the angular acceleration of the pulley and what is the ratio of the tension forces...

In the equation v=u+at, u=5 m/sec and a=0, then v=5 m/sec. That means the body is moving with a constant velocity of 5 m/sec. In a velocity-time graph, the equation produces a straight horizontal line. Some texts say the body is moving with zero acceleration and others say it is moving with...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] Initially the rod is in rotational equilibrium , so net torque about CM is zero . From torque equation about CM , we get Tension T in the left string = Force F (kx) in the spring Doing a force balance gives us T+F=Mg...

Homework Statement In this problem, the solution says that aB= -(aA/6). But from what I know, acceleration is positive whenever an object is speeding up in the positive direction or when an object is slowing down in the negative direction. According to the problem, car B is slowing down and...

Homework Statement Note : In the above setup the string lengths are unequal and the left angle is 30° and right angle is 60° .Homework EquationsThe Attempt at a Solution [/B] Just after the string is cut , writing force eq. for rod in vertical direction . ##Mg - Tcos60° = Ma_y ## (1)...

Not sure if I'm doing this right would love input Consider a box m=50kg which is being pulled on a rough, horizontal surface by a person using a rope . Assume that the person is applying a force of T=150N on the block , the rope makes an angle of 30 degrees with the horizontal and the...

Homework Statement Attached. Homework Equations Tangenital acceleration=r*alpha 3. The Attempt at a Solution I thought it was just simply r*alpha=2*20=40 (choice A), but the answer key says choice B. I'm not really sure where I could have went wrong or its possible that there is a mistake...

I want to determine the acceleration due to gravity at a place using a helical spring. For this, I've first calculated the extension in length of the spring (##x##) for a particular load (##L##) on the pan. Then I've plotted a graph for ##L## vs ##x## for different values of L and corresponding...

Homework Statement A thin uniform rod (of mass 10.0 Kg and length of 1.20 m) is attached to a friction-free pivot. Initially, the rod is balanced vertically above the pivot (position A in the figure attached). If the rod falls from rest, calculate a. the angular acceleration at position B...

Homework Statement Three lead spheres, of mass 10.0 kg each, are located at three corners of a square of ice length 45.0 cm, as shown. A bead is released at the forth corner. By considering the gravitational forces among the four objects only, determine the magnitude and direction of the...

A mass of 0.3 kg is suspended from a spring of stiffness 200 N m–1. If the mass is displaced by 10 mm from its equilibrium position and released, for the resulting vibration:Plot a graph of acceleration against displacement (x) (for values of x from x = –10 mm to x = +10 mm) Hugely struggling...

Consider a body of mass m at rest,then if I apply force f1 on that then it accelerates and attains a velocity of v1.then I remove that force..now the body is in uniform motion.if I apply a force f2 which is less than f1, then body will be accelerated or retardated?I know if same f1 is applied...

Set up: Gas on one side of a divider and an infinite vacuum on the other. Question: When you remove the divider, over time, does the gas increase in acceleration, does it peak and then decrease or does it remain the same as the gas enters the vacuum/ leaves the side opposite the vacuum?f Thanks

Homework Statement Homework EquationsThe Attempt at a Solution A) [/B] s = √[(x2) + (y2 ) ]= a√[2(1- cos (ωt) ) ]|t= Γ The book says, s = aωΓ What I can do is , For very small Γ i.e. ωΓ<<1 , cos (ωΓ) ≈ 1 - {(ωΓ)2}/2 Then , I get, s = aωΓBut, in question it is not given that ωΓ<<1. So...

Hi all, Since the gravitational acceleration varies depending on location, then how do you know if your scale is precisely calibrated? If I use a calibration weight (e.g. 100.000000 g) that was manufactured and tested around at equator where g=9.780 m/s^2, in my lab at the north pole where...

Homework Statement Given Ax,Ay,Az . I need to find the Vx,Vy,Vz ... The Coordinate Frame is Vehicle Axis System .. I have actual Speed to compare once i get the Vx,Vy,Vz ... The vehicle starts from the rest i.e Speed is zero and Accelerations are sampled at 0.05 seconds/// This is not a...

Homework Statement I am working on a project dealing with the velocity and acceleration of satellites based on their distance from Earth. I was recommended to include some calculus in this project. Originally I thought I could just take the derivative of the orbital speed equation to find...

1. Homework Statement this is a pulley system, each masses are moving with acceleration with a1,a2,a3.. question) 1) How can i calculate the ratio a1:a2:a3 ? 2) How can i calculate the T(tenstion)? 2. Homework Equations a1,a2,a3: acceleration of each masses. g=10m/s2 weight of all pulleys...

Homework Statement A small spring with a force constant of 72 N/m is held vertically and then stretched 16 cm. A 1.6kg mass is attached to it and then released. Calculate the acceleration of the mass at the moment of release. Homework Equations F = ma, Ee = 1/2kx^2 The Attempt at a Solution...

In uniform circular motion, direction of particle is changing at every moment but its speed remains the same. If the magnitude of velocity or speed remains the same, change in magnitude of velocity is zero. Then how come radial acceleration can have a calculated value since acceleration = change...

Homework Statement Two cars of 540 kg and 1400 kg collide head on while moving 80 km/h in opposite directions. After the collision, the automobiles remain locked together. Find the velocity of the wreck, the kinetic energy of the two-automobile system before and after the collision, and find...

according to f=GMm/r^2 if force changes based on a distance between 2 objects, so during free fall object is constantly changing its distance, so does that mean the Earth is exerting a non-constant force on that object? if that was right, why's that object accelerate at a constant rate of...

Please ignore strikeout (not sure why post is doing that) I just watched a video from Caltech (Video link at bottom of post) It says: Displacement = Distance Fallen in first second of time in [m] * Time2 so Time2 has no si unit as it is just a ratio right? Instant or Average Velocity = 2 *...

I understand that time slows with increased velocity and gravity, but even after reading this (article http://math.ucr.edu/home/baez/physics/Relativity/SR/clock.html) I'm a little confused as to whether or not acceleration alone, as in independent of (i.e., in addition to) velocity slows time...

Homework Statement I am investigating how much force (F) a person of a certain mass (m) would need to go down one of the world's tallest waterslides, "Killimanjaro" for an important maths project. Waterslide height: 49 m Maximum speed: 25.28 m/s Homework Equations I feel like I am not taking...

Homework Statement There is no friction between any surfaces mass is known. Find acceleration of the blocks. Homework Equations F=ma The Attempt at a Solution I'm almost certian Amx=g sin θ AMy=0

Homework Statement The 25-lb slender rod has a length of 6 ft. Using a collar of negligible mass, its end A is confined to move along the smooth circular bar of radius 32√ ft. End B rests on the floor, for which the coefficient of kinetic friction is μB = 0.24. The bar is released from rest...

Homework Statement There are two cars traveling in a same direction. The Second car has a camera mounted on it and has ability to give relative X and Y (in meters) distance of first car with respect to it. Given the Speed of Second car , Calculate the Speed and Acceleration of first car. The...

Homework Statement *Forgot to mention that this is a SHM question in the title Which of the following statements about an object that which perform an Simple harmonic motion is true? A) the acceleration is maximum when the velocity is maximum B) the acceleration is maximum when the displacement...

Homework Statement http://imgur.com/a/vA0H2 Homework Equations $$F=ma$$ $$r \times F = I \alpha $$ The Attempt at a Solution Denoting the forces at the back wheel with a 1 and front wheel with a 2 and calculating the torques around the CoM I have $$F-f_1-f_2 = mA$$ $$N_1 + N_2 -mg = 0$$...

Homework Statement In the following diagram a massless pulley is pulled by a constant force of magnitude P. There is no friction between the block and the floor. The acceleration produced in the block if mass m is? PIC ATTACHED Homework Equations Took a1/2=a2 where a1 is accn of block and a2...

Homework Statement Three identical rectangular blocks are at rest on a level, frictionless surface. Forces of equal magnitude that act in the same direction are exerted on each of the three blocks. Each force is exerted at a different point on the block (indicated by the symbol "x"), as shown...

Homework Statement A horizontal plank with a frictionless axis of rotation at its center has a large mass at one end and a small mass at the other end. It is held stationary and then released from rest. As the plank rotates (and before one end hits the ground), the magnitude of the angular...

So a light signal is sent off some space behind me. At the same time I start accelerating extremely quickly. Even though the light signal will always be faster than me it will never catch up with me. I have difficulties to understand that something that is always faster than you can still never...

Homework Statement A block of mass M = 10 kg is sitting on the table as shwoin Figure above. There is friction between the block and the table, the coefficient of friction is u = 0.1. The block has initial velocity V, and a constant forceF is applied to the black as showing Figure above. A)...

Today I've come across the statement that the coefficient of static friction of rubber tires on asphalt is bigger than that of tires on concrete. Does it mean that the maximal acceleration a car can attain on asphalt will be greater than that on concrete? My assumptions: 1)The force of friction...

Homework Statement A constant torque is applied to a pinion which has a moment of inertia of I_m. The pinion(A) drives two gears, one (B) which is connected to a mass which has a moment of inertia = I_m and the other(C) is connected to a mass which has a moment of inertia = 2I_m. The gear...

Hi All, I've been asked to re-work the below as my original method was incorrect. Below is my second attempt on the question, which I would appreciate some input from someone a more knowledgeable than myself. Thanks, 1. Homework Statement A racing car of mass 850 kg accelerates from 20...