Tagged Questions
0
votes
4answers
60 views
When we take time derivative of a function of time, then is the result another function of time, again?
(I'll try to explain my question by one known example), for example where the velocity is a function of time v(t) then its time derivative (which is acceleration: $a=\frac {dv}{dt}$) is another ...
-3
votes
0answers
24 views
Length Traveled from Complete Stop [closed]
A one-meter long rifle fires a bullet at a velocity of 800 m/s. What is the average acceleration experienced by the bullet when it is fired? (Hint: You need to find the time it takes the bullet to ...
6
votes
4answers
148 views
Integrating radial free fall in Newtonian gravity
I thought this would be a simple question, but I'm having trouble figuring it out. Not a homework assignment btw. I am a physics student and am just genuinely interested in physics problems involving ...
-1
votes
1answer
96 views
Elevator acceleration and velocity equation [closed]
I have a small question about the velocity and the acceleration of elevators.
I am looking for equations which is for a constant velocity and acceleration ( for exemple some elevators didn't have a ...
8
votes
2answers
291 views
Is acceleration an average?
Background
I'm new to physics and math. I stopped studying both of them in high-school, and I wish I hadn't. I'm pursuing study in both topics for personal interest. Today, I'm learning about ...
1
vote
1answer
126 views
Utilizing maximum acceleration $a$ for displacement $d$ with initial velocity $v_0$ and final velocity $v_1$
Problem
My goal is to move an object from point a to b (displacement $d$) as fast as possible utilizing the maximum available acceleration $a_{max}$, taking into account the initial velocity $v_0$ ...
0
votes
1answer
94 views
Kinematics with non constant acceleration
A particle experiences an acceleration described by
$$
a=kx^{-2}
$$
where x is the displacement from the origin and k is an arbitrary constant.
To what value does the velocity v of the particle ...
3
votes
2answers
70 views
Sign of acceleration
I'm developing an application using accelerometer sensor. I'm not good at physics so forgive me if the question is trivial. If I have 3 values of acceleration: $x$, $y$, $z$, I find acceleration ...
0
votes
3answers
309 views
Deriving equations of motion using integration
Please refer to my school textbook pg48 (of the book, and not the pdf counter) here: http://ncertbooks.prashanthellina.com/class_11.Physics.PhysicsPartI/ch-3.pdf
My doubt is in this context: (right ...
0
votes
0answers
87 views
An unmarked police car passed by a speeding car [closed]
Hi I'm trying to solve the problem
An unmarked police car traveling at a constant speed of 95 km/h is passed by a speeder traveling at 140 km/h. Precisely, 1.00 s after the speeder passes, the ...
0
votes
1answer
108 views
Kinematics question [closed]
An electric train accelerates uniformly from rest to a speed of 20m/s which it maintains until the brakes are applied. It is then brought to rest by a uniform retardation equal in magnitude to twice ...
0
votes
2answers
116 views
Do you use the magnitude equation to get speed from an accelerometer?
A guy suggested to me that getting speed from an accelerometer required the use of this equation:
$\text{speed} = \sqrt{x^2 + y^2 + z^2}$
This does not make any sense to me, all that you would get ...
2
votes
1answer
181 views
Calculate displacement in position from knowing constant acceleration
I have recently started studying physics at school, and my teacher went over the following equation without explaining about it too much:
$$d~=~vt+\frac{1}{2}a t^2.$$
I have wondered, why would this ...
0
votes
2answers
147 views
How can I add an acceleration vector to a velocity with a different direction?
I am in my last year of high school and am struggling with some homework. I'm sorry if this question is incredibly stupid, but I simply can't find the answer in my notes.
If I have an object with a ...
0
votes
0answers
57 views
At an acceleration of 2ft/s^2, how fast could I reach 9.8MPH? [closed]
Question title is self explanatory.
If I'm accelerating at $2ft/s ^{2}$, how long does it take to reach $9.8MPH$?
0
votes
0answers
86 views
Physics about plane take off simple find the acceleration problem [closed]
This was on my test, but I kinda botched it I think.
I was trying to use
V^2f = Vo^2 + 2a(delta x)
A plane must reach 226km/h to take off. Runway is 2000m. What's minimum acceleration needed? ...
0
votes
2answers
83 views
6
votes
4answers
479 views
How to brake 'beautifully'?
Sometimes when I'm driving my car, I play a "game" against myself in which I try to minimize the deceleration felt by passengers (including myself) while still braking in a reasonable short space. I ...
0
votes
2answers
117 views
Negative sign of acceleration [closed]
This is the problem from our Physics textbook :
A player throws a ball upwards with an initial speed of 29.4 m s–1.
(a) Choose the x = 0 m and t = 0 s to be the location and time of the ball at ...
-2
votes
1answer
443 views
Calculate acceleration and time given initial speed, final speed, and travelling distance? [closed]
A motorcycle is known to accelerate from rest to 190km/h in 402m.
Considering the rate of acceleration is constant, how should I go about calculating the acceleration rate and the time it took the ...
0
votes
3answers
604 views
Calculating car's acceleration from change in angle of hanging object?
The question essentially is based on a situation like this-
A car has a small object hung from the cieling on a string (apparently at an angle of 0 degrees to the ceiling).
The car is accelerating ...
0
votes
2answers
306 views
Center of gravity of vehicle and vehicle performance
I am interested to know how does CG of vehicle plays role in the Fuel economy and the vehicle performance. Does CG of vehicle has anything to do while accelerating of your vehicle. I am a student, ...
3
votes
2answers
697 views
How can an object's instantaneous speed be zero and it's instantaneous acceleration be nonzero?
I'm studying for my upcoming physics course and ran across this concept - I'd love an explanation.
0
votes
0answers
76 views
Does human body parts like hand or leg move with uniform acceleration?
So is this true. I mean does a movement by hand or leg make uniform or constant acceleration?
0
votes
2answers
291 views
Time and distance where velocity is a function of time
I'm creating a video game set in space in which spaceships travelling between places accelerate until they hit a maximum velocity. They then travel at that velocity until a time when they need to ...
0
votes
3answers
378 views
Finding instantaneous speed in MPH given acceleration, RPM and gear ratio
I am still trying to figure out how to (semi) accurately model instantaneous speed after having found acceleration. I have found that at higher RPMs, the resultant acceleration will be lower. I was ...
2
votes
2answers
912 views
Finding acceleration for a car after finding torque
I am trying to calculate the acceleration of a vehicle after finding the torque $\tau$. Assuming my Horse Power is 130 and my RPM is 1000, I calculated torque as:
$$\tau = \frac{130 \times ...
3
votes
1answer
142 views
A practical deceleration question
My friend is a U.S. Army paratrooper. Today, through an unfortunate series of events, he was jerked out of a C-17 traveling at 160 knots by his reserve parachute. First-hand accounts describe it as he ...
0
votes
2answers
279 views
Does acceleration at an angle to velocity change the direction?
During an interval of time, a tennis ball is moved so that the angle between the velocity and the acceleration of the ball is kept at a constant 120º. Which statement is true about the tennis ball ...
1
vote
1answer
617 views
How to find acceleration given position and velocity?
Sorry for this very simple question but I am still very new to the laws of motion.
I am dealing with 2-dimensional vectors in my programming environment and I'm following these slides to learn about ...
1
vote
2answers
75 views
Acceleration: Value Disparity?
If we consider a ball moving at an acceleration of $5ms^{-2}$, over a time of 4 seconds, the distance covered by the ball in the first second is $5m$. In the 2nd second will $5 + 5 = 10m$. In the ...
1
vote
2answers
219 views
Using acceleration to plot position
Sorry if this question is dumb, and I know is physics 101, but I'm not that good with physics.
I'm writing an iPhone program that by collecting the acceleration data of the device tries to replicate ...
0
votes
2answers
315 views
How to calculate total distance and time a puck will move?
To simulate a puck's movement, I use the following model (please restrain from discussing the model, it makes the simulation look the way I want it to) and would like to know how to calculate the ...
1
vote
0answers
187 views
How to model an accelerometer measurements on a car wheel?
I am working on kinematically modelling an accelerometer on a car wheel.
When working on the initial conditions, I am confused whether or not I should use the gravitational acceleration since there ...
1
vote
2answers
149 views
Is it possible to calculate specific velocities from acceleration?
I'm trying to understand a sample problem from a current (published 2011) high school physics textbook, but I really think the question is flawed. The task is to convert an acceleration-time graph ...
0
votes
1answer
114 views
Find the acceleration based on V² x d graph
How could I find the acceleration of a body knowing only that its position and velocity satisfy $v^2 = f(x)$, where $f(x)$ is a known function of $x$ (position)?
4
votes
5answers
4k views
Distance when acceleration not constant
I have a background in calculus but don't really know anything about physics. Forgive me if this is a really basic question.
The equation for distance of an accelerating object with constant ...
7
votes
2answers
834 views
Should acceleration be included in state vector of a Kalman filter?
I'm developing (actually adopting existing solution) a Kalman filter to model motion of a vehicle (UAV or automobile). The state vector will include position, velocity, and, possibly, acceleration.
...
3
votes
3answers
3k views
Ion Drive Propulsion Top Speed
I would like to know if there is some formula / graph which would provide / show the efficiency of a certain type of propeller in space. Specifically, I'm interested in the acceleration attainable at ...
1
vote
3answers
4k views
Find radius of curvature, given a velocity vector and acceleration magnitude?
The particle P moves along a space curve. At one instant it has velocity $v = (4i-2j-k)$ $m/s$. The magnitude of the acceleration is 8 $m/s^2$. The angle between the acceleration and the velocity ...
0
votes
2answers
131 views
In a 2D problem with a thrown object, why is the acceleration along the x-axis equal to 0?
I'm starting Physics, and I don't understand why the acceleration along the x-axis is zero for an object thrown near the surface of the Earth. This may be problem specific, but I wouldn't know since I ...
3
votes
2answers
971 views
Formulas for ball rolling in a bowl?
I'm developing a program where I've a ball/sphere rolling in a bowl from the side at top, till the center at bottom, and I'm trying to get the formulas for:
The rotation angle and the position of ...
0
votes
3answers
245 views
Deccelerate and Accelerate to achieve timed journey
I have a vehicle traveling at initial speed $100\:\mathrm{m/s}$.
Expected destination speed is also $100\:\mathrm{m/s}$.
Maximum deceleration is $3$.
Maximum acceleration is $10$.
Distance to the ...
0
votes
2answers
4k views
Stopping Distance (frictionless)
Assuming I have a body travelling in space at a rate of 1000m/sec. Let's also assume my maximum deceleration speed is 10m/sec*sec. How can I calculate the minimum stopping distance of the body?
All ...
