What is Acceleration: Definition and 1000 Discussions
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time.
Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the orientation of the net force acting on that object. The magnitude of an object's acceleration, as described by Newton's Second Law, is the combined effect of two causes:
the net balance of all external forces acting onto that object — magnitude is directly proportional to this net resulting force;
that object's mass, depending on the materials out of which it is made — magnitude is inversely proportional to the object's mass.The SI unit for acceleration is metre per second squared (m⋅s−2,
m
s
2
{\displaystyle {\tfrac {\operatorname {m} }{\operatorname {s} ^{2}}}}
).
For example, when a vehicle starts from a standstill (zero velocity, in an inertial frame of reference) and travels in a straight line at increasing speeds, it is accelerating in the direction of travel. If the vehicle turns, an acceleration occurs toward the new direction and changes its motion vector. The acceleration of the vehicle in its current direction of motion is called a linear (or tangential during circular motions) acceleration, the reaction to which the passengers on board experience as a force pushing them back into their seats. When changing direction, the effecting acceleration is called radial (or orthogonal during circular motions) acceleration, the reaction to which the passengers experience as a centrifugal force. If the speed of the vehicle decreases, this is an acceleration in the opposite direction and mathematically a negative, sometimes called deceleration, and passengers experience the reaction to deceleration as an inertial force pushing them forward. Such negative accelerations are often achieved by retrorocket burning in spacecraft. Both acceleration and deceleration are treated the same, they are both changes in velocity. Each of these accelerations (tangential, radial, deceleration) is felt by passengers until their relative (differential) velocity are neutralized in reference to the vehicle.
What is the difference between tangential and linear acceleration of a circular object (let's say a ball)? Also, how does the torque contribute to linear acceleration?
Homework Statement
A car travels over a hump in the road of radius 20 meters. How fast is the car traveling if the occupants feel a net acceleration of 3.8 m/s2
Homework Equations
a = v2/r
v = √ar
The Attempt at a Solution
I did this but according to my teacher this isn't correct.
v = √(3.8...
Homework Statement
A block of mass 0.5Kg rests on the inclined surface of a wedge of mass 2kg. The wedge is acted on by a horizontal force that slides on a frictionless surface. If the coefficient of static friction between the wedge and the block is 0.8 and the angle is 35 degrees, find the...
Homework Statement
A physics student studying gravity on the surface of Mars, throws a ball into the air at time t=0s. The ball follows a parabolic trajectory as shown and reaches a maximum height height at t=2s. At t=1s the velocity of the ball is v(t=1s)= 2.00 m/s i + 3.72 m/s j where i and j...
Hi please don't butcher me, I'm really not a crackpot...just not sure how to put this or were to post this...on particle acceleration...i have heard of things called micro singularities...are these real could they be used for an alternative energy source...really just curious it seems like...
Homework Statement
I understand in my head that Wx = mgsin(27) and Wy = -mgcos(27). Though when I tried solving for both Wx and Wy, their signs turned out to be opposite. I've provided my work leading up to Wx = -mgsin(27) and Wy = mgcos(27). Maybe I interpreted the signs of x and y component...
Homework Statement
Homework Equations
F = ma
The Attempt at a Solution
The solution to the problem is 1.12m/s^2. However, I don't know how they got to that number. Every way I do it I end up with 3.2m/s^2.
Homework Statement
When the motor in the figure below lowers the m = 1200kg mass, it produces a tension of 1.15E+4N in the cable on the right side of the pulley. The pulley has a moment of inertia of 71.3kgm^2 and a radius of 0.794m. The cable rides over the pulley without slipping. Determine...
A non-moving observer is looking at two different rockets in space. One rocket is moving at a steady velocity of 0.5c, and the other rocket is currently moving in 0.5c but has steadily accelerated from 0.3c and will continue accelerating until it gets to 0.7c.
Assuming that there is no...
Homework Statement
A 12.0-kg box is pushed along a horizontal surface by a 24-N force as illustrated in the diagram. The frictional force (kinetic) acting on the object is 6.0 N
A) What is the acceleration of the object
B) Calculate the value of the normal force acting on the object
C) If the...
So I am having trouble with a problem.. and this has been a thorn in my side for quite some time now. I am working on a science fiction idea where I use the rate of expansion of the universe as the rate of acceleration of a spaceship. The rate of expansion is about 70 km/sec/megaparsec.. and I...
Homework Statement
Two cars are 1.4 km apart and driving towards each other. One car starts from rest and accelerates uniformly at 1.2 m/s^2. The other car is driving at a constant speed of 18 m/s. When will the cars meet?
Homework Equations
d=vt
d=ut + 1/2at^2
d=vt-1/2at^2
v^2 = u^2 + 2ad...
Homework Statement
A thin, uniform, 18.5 kg post, 2.10 m long, is held vertically using a cable and is attached to a 5.00 kg mass and a pivot at its bottom end (as shown below). The string attached to the 5.00 kg mass passes over a massless, frictionless pulley and pulls perpendicular to the...
Homework Statement
Two objects of 2.8kg and 4.2kg are connected by an inextensible cord. The object's at rest on a plane inclined 22°, determine the object's acceleration and tension in the cord if a 60N force is used to push the object downward.
Homework Equations
ΣFnet = ma
the plane is...
Homework Statement
Homework EquationsThe Attempt at a Solution
it is known that
##a_0
##is the proper acceleration
##
a= \frac{a_0}{\gamma^3}
##
hence integrating it gets
##
v = \frac{a_0t}{\sqrt{1 + (\frac{a_0 t}{c})^2}}
##
but this is in terms of t how to make it in terms of t'
Homework Statement
d=Vi t + 1/2at^2
What do each of these mean? Show that this is true
d=vt-Solve
v=Vf+Vi/2 - Substitute Vf with Vf= Vi+at
Homework Equations
v= average speed
Vi=initial speed
Vf= final speed
The Attempt at a Solution
Vit: This represents the initial velocity at said time...
Homework Statement
In lab, we put a glider on an airtrack and used a pulley to move the glider. The mass on the pulley was changed with each iteration. I have created a graph to find the mass of the glider, but I don't know what the y-intercept is supposed to mean. The graph I have is linear...
Hi all, I've been lurking around the forums for a while to get help with homework but I figured I'd finally make an account to get direct feedback.
I'm having problems with this centripetal acceleration problem, Homework Statement
"In an old-fashioned amusement park ride, passengers stand...
Homework Statement
acceleratin as function of time
##a(t)= 2t+1##
we know that v(0)=0
and s(0)=0
find v(t)
find v(5)
find s(t)
find s(3)
and I was thinking about also what happens when t is negative number,
is it possible to find also v(-2)?
what about s(-3)?
Homework Equations
integration...
Homework Statement
Rigid body (ship) rotate and moves around 3 axis (x,y,z) around the center of gravity. The position is of the center of gravity is not known.
What is known: At a point (A) the accereleration, velocity and position and rotational acceleration, velocity and position are known...
I have to be missing something very obvious in this.
Homework Statement
A car travels 80km/h on a level road in the positive direction of an x axis. Each tire has a diameter of 66 cm. Relative to a person riding in the car, what is the velocity of a) center, b)top, and c) bottom of the tire...
Homework Statement
13.53 The tension in the sting of the simple pendulum is 7.5N when θ=30deg.
Calculate the angular velocity and angular acceleration of the string at this instant.
Homework EquationsThe Attempt at a Solution
Is this correct?
(context) I can remember reading about an atomic clock that could show time running slightly differently rates at different heights, due to the differences in gravitation.
Is it realistic to think of it the other way round, ie gravity as an effect of miniscule time rate difference ?
If an...
Homework Statement
A bowling ball sits on the smooth floor of a subway car. If the car has a horizontal acceleration a, what is the acceleration of the ball? Assume that the ball rolls without slipping.
Homework Equations
torque = R x F = Iα
aball= Rα
Isphere = (2/5) MR2
The Attempt at a...
https://drive.google.com/file/d/0B0NXDy0RMDe7MXhMcjZBdkhoSDg/view?usp=sharing
PIC: [https://drive.google.com/file/d/0B0NXDy0RMDe7MXhMcjZBdkhoSDg/view?usp=sharing]
1.
A rotating disk is connected with two arms AD and DB which are rotating with the rate of 0.2 rad/s^2 and -0.3 rad/s^2...
Hello, I was working on a worksheet. It gave a graph that was velocity vs. time. I was asked to find the acceleration rate for the given (specific) time in seconds. My first question is if the line on the graph for example is from 1-3 seconds, in that 1-3 second range, is acceleration constant...
Question: A car is moving north at 100km/h. An hour later it is moving east at 100km/h. Its average acceleration during this hour is:
a) A vector pointing northeast
b) A vector pointing southeast
c) A vector pointing southwest
d) A vector pointing east
e) Zero
Attempt: I confidently chose a) A...
Homework Statement
A frictionless surface is inclined at an angle of 30.0° to the horizontal. A 270-g block on the ramp is attached to a 75.0-g block using a pulley, as shown in Figure 4-62. (a) Draw two free-body diagrams, one for the 270-g block and the other for the 75.0-g block. (b) Find...
1. Homework Statement
Given x and y position ... find magnitude of both velocity and acceleration and their direction at t = 2 ?
x = 4t
y = 30 - 2.2t^2
would the velocity's magnitude be sqrt(8^2 + 8.8^2) ?
Homework Equations
v = sqrt(vy^2 + vx^2)
The Attempt at a Solution
vy = -8.8
vx= 8...
Homework Statement
Homework Equations
F= maThe Attempt at a Solution
For 8, I think the parachute causes Al and Betty to stop accelerating, so they both have the same net force. (Answer A)
F= ma
F=m*0=0
F=3m*0=0
For 9, I feel like Al should experience more air resistance than Betty to make...
Homework Statement
A train has a length of 118 m and starts from rest with a constant acceleration at time t = 0 s. At this instant, a car just reaches the end of the train. The car is moving with a constant velocity. At a time t = 14.0 s, the car just reaches the front of the train...
Homework Statement
A person is standing on an elevator initially at rest at the first floor of a high building. The elevator then begins to ascend to the sixth floor, which is a known distance h above the starting point. A plot of the acceleration as a function of time is shown in the figure...
Homework Statement
A person standing on a train platform notices that the first train car, which is approaching the station, had passed him in 4 seconds, and that the second train car passed him in 5 seconds. After this, the front of the train stopped at the distance of 75 meters from the...
Homework Statement
Imagine a ball on a string that we swing vertically so that the hight changes. By conservation of energy the velocity of the ball must change right? Because at the highest point of the swing it will have maximum GPE but at the bottom, minimum right? Watching many videos has...
I was assuming that the proper time lapse between ##r=2M## and ##r=0## increases with increasing acceleration outwards.
According to this paper
https://arxiv.org/pdf/0705.1029v1.pdf Fig.2.
it turns out however that the proper time to reach the singularity is longer with low acceleration but...
I’m trying to calculate the theoretical jerk and acceleration curve/distance/time for an elevator.
I have the constant starting jerk set to 1m/s3, constant acceleration set to 1m/s2 and full speed set to 1m/s.
Looking at Wikipedia about both, I can work out the figures about acceleration but I...
I have collected data on a car accelerating down a straight track. I graphed it Position vs Time. Then I found the tangent slope at 5 points along the curve and plotted them as velocity. But then I linearized the position vs Time graph (position vs Time^2.) However, the slope of the velocity vs...
Hello Forum,
If a force is a function of position x only, like Hooks's spring force F=-kx, the acceleration is also only dependent on the position x, i.e. a(x).
At every instant of time t, the object has a specific velocity v(t), position x(t) and acceleration a(t), which all depend on the time...
Hi! So someone came up to me with this question during physics and its been bothering me because I didn't know what to say to them and I didn't know if my understanding is correct or not. The question was something like:
" A 72 kg car is traveling at v=63km an hour when it gets into a...
Homework Statement
Masses M and m are connected to a system of strings and pulleys as shown
in the diagram below. The strings are massless and inextensible, and the p
ulleys are massless and
frictionless.
A: Find the accelerations for M and m (Hint: Think about these two questions:
Do these two...
That is to say, how does time behave in a region of space where multiple gravitational fields cancel out their accelerating effects?
I understand that time "slows down" in a gravitational field, but does this depend on the actual presence of the field, or instead the actual net acceleration...
Hello,
I was referring to this thread: https://www.physicsforums.com/threads/accelerating-atwoods-machine-problem.44305/ to solve a problem on accelerating atwood machines in which, naturally, one attempts to find the acceleration of each of the individual masses.
Although I now understand how...
Homework Statement
13.34 The curved portion of the cloverleaf highway interchange is defined by
##R^2=b^2sin2θ##, 0<=θ<=90deg. If a car travels along the curve at the constant speed v0,
determine its acceleration at A
Homework EquationsThe Attempt at a Solution
[/B]
Is this wrong?
Homework Statement
At one instant a bicyclist is 20.5 m due south of a park's flagpole, going due east with a speed of 14.1 m/s. Then, 3.95 s later, the cyclist is 36.3 m due west of the flagpole, going due north with a speed of 18.3 m/s. For the cyclist in this 3.95 second interval, find each...
Homework Statement
A car is moving with a constant velocity of 18 m/s for 5 seconds, if in the next 5 seconds it travels a distance of 40 m, what is its final velocity?
Homework Equations
Δx= vit+ 1/2 at^2
vf= vi+at
vf^2 = vi^2 + 2a (Δx)
The Attempt at a Solution
So I tried doing it different...
Homework Statement
The mine skip is being hauled to the surface over the curved track by the cable wound around the 38-in. drum, which turns at the constant clockwise speed of 96 rev/min. The shape of the track is designed so that y = x2/28, where x and y are in feet. Calculate the magnitude of...
In uniform curved motion , I can get the acceleration from the equation :
A = v2/r , but in non uniform the velocity is changing , so will the certipetal acceleration also change ?
A nucleon that consists entirely of two or more protons, would be accelerated evenly, as each proton would see the same force (barring any collisions or other extraneous events.) Each should experience the same force of repulsion or attraction that is causing them to accelerate, so they should...
(Mentor note) This thread was moved from another forum, hence no homework template.
How do you deduce initial acceleration just from B, L, M, and I? (Telsa, length, mass, and current)
1. Homework Statement
It's an auto closing gate. Two parts of the gate are identical. I had given to find the time taken to close the gate. The distance to close point (P) of the gate from closed event of the gate is given as "a". Sorry for my bad English.
What i need to know is how the two...