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3
votes
5answers
934 views

What is the difference between uniform velocity and constant velocity?

I think that uniform velocity implies constant speed but not constant direction. while constant velocity implies constant speed without any changes in direction. Both tell us that there's no ...
1
vote
4answers
93 views

Problem on circular motion

If a body moves such that its net acceleration always points towards a particular point does this body have constant angular velocity around this point?
0
votes
0answers
87 views

Angle between velocity and acceleration vector, and interpretation of pathway [closed]

I just started studying mechanics, and I am stuck with the following question: $$\vec{r}(t)=a \sin(\alpha t^2)\hat{x}+b \cos(\alpha t^2)\hat{y}$$ I was asked to find the formula that expresses the ...
1
vote
2answers
85 views

How can I understand if an object stay (zero velocity) or moving with constant velocity (zero acceleration)

I thought a scenario like; lets say I am looking an object and there is nothing except this object. Is there a way to understand that if this object is stay on its position or if object moving with a ...
1
vote
5answers
68 views

Equation of distance and time

How is this equation derived? $$r = r_0 + ut + at²/2$$ where $r_0$ is the initial position of particle and $r$ is the position of the particle after all the motion it has undergone, $a$ and $t$ ...
18
votes
9answers
6k views

The instant an accelerating object has zero speed, is it speeding up, slowing down, or neither?

This problem is from Khan Academy. Specifically for the blue point circled in red, the answer is that at this blue point, the object is neither speeding up nor slowing down. When I think about the ...
0
votes
2answers
28 views

Intuition of Distance covered when accelerating [duplicate]

When you're moving at $5$ m/s for $1$ second, you have traveled $5$ m. When you're moving at $5$ m/s (initial velocity) and you accelerate $2$ m/s for $1$ second, you have traveled $5$ m + $1$ m (...
-1
votes
1answer
60 views

Use of direction of downward velocity in equation of motion

[NOTE: I am not asking anyone to solve the question below but to point out where I might be wrong] Q- A skier jumps from a horizontal track and lands on a steeper track with a launch angle of ∅=11.3°(...
5
votes
2answers
147 views

What is the meaning of transverse acceleration due to work in special relativity?

If we derive the momentum in Special Relativity we get : $$ \dfrac{\mathrm{d}\boldsymbol{p}}{\mathrm{d}t} = \dfrac{\mathrm{d}m \gamma \boldsymbol{v}}{\mathrm{d}t} = m\dot{\gamma}\boldsymbol{v}+m\...
1
vote
2answers
38 views

Is it possible to estimate linear displacement using accelerometer & gyroscope with the kinematic equations of motion?

I am trying to estimate linear displacement using a 9DOF inertial measurement unit. My question is: After correcting the accelerometer readings using the gyroscope, is it possible to apply the ...
1
vote
1answer
31 views

Calculating acceleration of an object using $x$, $y$ and $z$ coordinates

I have x, y and z coordinates for a test I had carried out for a tool. I had an accelerometer installed on the tool and I used two types of motion to move the tool, rotation and translation. Right now ...
0
votes
4answers
102 views

What does a negative acceleration mean? Is the object slowing down, changing direction, or both?

I am confused about such things as negative velocity, acceleration, and displacement and what the negative indicates.
1
vote
2answers
68 views

Is motion smooth? [duplicate]

It's obvious that for every particle velocity is smooth i.e it cannot undergo sudden finite change in its position in infinitisiminal time. Similarly any particle's velocity cannot undergo a change ...
-1
votes
1answer
33 views

Finding tangential and normal velocity from a curve [closed]

How do you find tangential and normal velocity from a curve? I know how to find dy/dx, but I have no idea how to obtain ut and un and dv/dt.
0
votes
0answers
55 views

Why don't we define time derivative of acceleration? [duplicate]

When we started the study of kinematics we defined position and its change with respect to time. After that we defined time derivative of velocity which gave us acceleration. These 3 concepts really ...
1
vote
7answers
96 views

Is there centripetal acceleration with velocity of 5 m/s?

So if an object is moving at $5\ \mathrm{m\ s^{-1}}$ in a circle, is it accelerating? Me and a friend are having a conversation about this.
5
votes
4answers
373 views

Is there a scalar acceleration?

Distance is paired with Displacement and it seems to be a bigger idea than just the magnitude of Displacement. Speed is paired with Velocity. I have always thought that there is not such pairing with ...
1
vote
0answers
27 views

Calculating time taken for acceleration [closed]

about tickertape timer,when we measure the time for a particular object's acceleration, we would take 7 ticks multiply 0.020s(for example), instead of taking 8 ticks. Why do we exclude the other tick, ...
0
votes
2answers
40 views

Speed and tangential acceleration in pendulum motion

Speed is a scalar quantity which corresponds to the magnitude of velocity, so it must always be nonnegative. In a general 2d motion, the tangential component of acceleration is given by the time ...
0
votes
2answers
69 views

If an object in free-fall is moving upward, the object's velocity is decreasing. Does this mean that the acceleration is -9.8 m/s/s?

I have a problem (that I am not asking you to solve) where it takes $4s$ for an object to travel upward to its maximum height, and we have to determine how far the object travelled. If the ...
0
votes
1answer
34 views

Change of variable in function

Suppose I have a function $h(\theta)$ measuring the height of a piston, with $\theta = \omega t$. I would like to know the vertical acceleration of this piston as $\omega$ changes at the point $\theta ...
3
votes
2answers
108 views

How to decelerate from velocity $v$ to stop time $t$ over distance $d$? [closed]

I'd be grateful for some help with this problem I am trying to solve. Let's say that I have an object travelling at a velocity $v$. I want that object to come to a halt in time $t$ AND travel exactly ...
1
vote
2answers
112 views

Find the time when tangential acceleration is equal to radial acceleration [closed]

A particle begins to move along a circular path of radius R with a constant magnitude tangential acceleration of $a_t$. After time $t$ it's the centripetal acceleration is equal in magnitude to ...
0
votes
2answers
99 views

How does centripetal acceleration have direction/vector and magnitude while in the formula $v^2=v\cdot v$ is scalar?

$$a_c=v^2/r$$ 1. How does centripetal acceleration have direction or vector while in the formula dot product between velocity vector is scalar (as in kinetic energy)? Radius is scalar quantity. What ...
0
votes
1answer
51 views

In the equation for acceleration (with known $v$, $u$ and $s$) why velocity is squared and displacement is multiplied by 2? [closed]

In the following equation $$a = \frac{v^2 − u^2 } {2s} ,$$ where $v$ is the final velocity, $u$ is the initial velocity, and $s$ is displacement. Why is velocity squared and displacement multiplied by ...
0
votes
2answers
46 views

Intuition for formula of tangential component of acceleration in general curvillinear motion

In certain problems of plane motion, the position of the particle P is defined by its polar coordinates $r$ and $\theta$. It is then convenient to resolve the velocity and acceleration of the particle ...
0
votes
1answer
69 views

Why $g$ on equator is less than $g$ on poles? [duplicate]

I found this on my physics book. The book says $g$ on equator 9.78 $m/s^2$ and on the poles 9.81 $m/s^2$. Is it due to gravity?
0
votes
1answer
60 views

When a body completes one revolution around a circular path will its acceleration be 0?

When a body is moving in a circular motion the acceleration keeps changing, will it be zero when it comes back to the same point it started from(will the average acceleration be 0?)
0
votes
0answers
43 views

Acceleration as the second derivative of displacement function

Let $x$ be displacement as a function of time $t$ and some other physical quantity $k$ such that $ x = f(t,k) $ Now, 1) Will the acceleration $a$ be $\frac{\partial^2 x}{\partial t^2}$ or $\frac{d^...
1
vote
0answers
53 views

Does the proper four-acceleration $A^{\mu} = (0,0)?$

Let the proper four-position vector $x^{\mu}(\tau) = (0, \tau)$. Differentiating this successively wrt $\tau$ I get the four-velocity $u^{\mu}(\tau) = (0, 1)$ and then the four-acceleration $A^{\mu}(\...
1
vote
2answers
233 views

Can an object have constant speed and tangential acceleration without undergoing circular motion?

Is it possible for an object to be moving with constant speed and a constant magnitude of acceleration tangent to this velocity but NOT move in a circular path? If there are other situations could I ...
1
vote
4answers
103 views

Instantaneous changes in acceleration

These are very simple looking graphs. What I don’t understand is (I’m talking of the highlighted text in blue at the bottom), it says such instantaneous changes in acceleration can not occur in ...
0
votes
8answers
1k views

Why is acceleration variable in uniform circular motion?

Acceleration is the rate of change of velocity. In the uniform circular motion the acceleration is produced due to change of direction of the velocity(the magnitude remains same). The direction is ...
1
vote
3answers
122 views

If there was but one object in the universe, can it be accelerating or not accelerating?

If there is only a single (material) object in the universe does it still make sense to speak of it as accelerating or not accelerating? I believe it might be an equivalent question to ask whether it ...
12
votes
7answers
1k views

Can we divide a vector by another vector? How about this: $a = vdv/dx?$

My physics teacher told us that we can’t divide vectors, that vector division has no physical meaning or significance. How about this: $$a = vdv/dx.$$ It says acceleration vector equals velocity (as ...
0
votes
3answers
71 views

Effect on speed when decreasing the magnitude of acceleration

I'm struggling to come up with an answer to the following situation and question: "Suppose you are driving your car along a straight road in the positive direction and are speeding up (increasing ...
0
votes
1answer
49 views

Acceleration formula derivation (newtonian physics) [closed]

Acceleration has a simple equation in physics: $$a = \frac{(v-u)}{t}$$ (should be $\Delta v / \Delta t$) Both $v$ and $u$ have $s/t$ as their formula. So, dividing twice by time gives time squared, ...
-1
votes
2answers
706 views

The human body can survive an acceleration trauma incident (sudden stop) if the magnitude of the acceleration is less than [closed]

The human body can survive an acceleration trauma incident (sudden stop) if the magnitude of the acceleration is less than 250 m/s². If you are in an auto- mobile accident with an initial speed of 105 ...
0
votes
1answer
75 views

How to Find Jerk from Discrete Velocity Data?

I have measured the velocity of an object at discrete intervals. I want to find the corresponding acceleration and jerk of the object. How do I do this with discrete values rather than continuous ...
0
votes
2answers
139 views

What would the position vs. time graph look like if the velocity vs. time graph was a curve?

In my physics class we are learning about velocity vs. time graphs and position vs. time graphs for an object. We have learned that if the object is moving with constant velocity (this would be a ...
0
votes
3answers
65 views

How to know which constant acceleration equation to use? [closed]

The question I'm working on: This is the answer: For (b), I just want to know why we use ((v+u)/2)t) to find the displacement of the mailbag. It is clearly a free falling object that has ...
0
votes
1answer
18 views

Average Velocity Question (isolation?)

So there is this question i've been having trouble with for the past hour. It involved a child going down a ramp on a sled at and angle theta with a total system of mass. accelerates down a hill of ...
0
votes
5answers
118 views

How to determine the direction of a vector?

I have been learning about vectors and acceleration recently and I still don't understand how to determine the direction of a vector. For instance, if we consider a freely falling particle and ...
0
votes
5answers
46 views

Why do objects move back after collision?

When a ball collides with a wall, the ball moves in the opposite direction, why does this happen if Newton's third law operates. I mean the ball collided with the wall and imparted a force on it and ...
0
votes
1answer
40 views

Acceleration in $x$ and $y$ directions of a pendulum swinging? [closed]

If there is a pendulum that gets released and only moves in two dimensions, what would it’s acceleration be in the x and y directions, meaning at what rate is the velocity changing in the x and y ...
49
votes
14answers
20k views

Why doesn't a braking car move backwards?

The net force on an object is equal to the mass times the acceleration, $F = ma$ When I brake on a (moving) car, the net force is negative, therefore causing the resulting acceleration to also be ...
3
votes
2answers
160 views

Does Euler number $e$ have a role in kinematics?

Euler number $e$ is often explained with the example of compound continuous interest. I was wondering if it could also be illustrated with an example about the displacement of a body (although not an ...
0
votes
2answers
91 views

Confused with derivative and partial derivative

suppose $x=f(t)$ with a constant acceleration. Then does $\frac{\text d x}{\text d t} = \frac{\partial (x)}{\partial(t)}$ since the position in $x$ only changes with time? Then the acceleration in ...
0
votes
1answer
42 views

Interpreting derivatives

So we have a function such that the distance moved by a particle (say $s$) is proportional to $sin(Ct)$ where $C$ is a constant. Now i needed to show that the rate of change of velocity is directly ...
-1
votes
2answers
51 views

Lateral acceleration to angle [closed]

I am doing a 2D simulation in discrete steps of a vehicle. The vehicle will desire a certain lateral acc. at any given timestep. So I would like to know the delta angle of the velocity vector after ...