The description of the movement of bodies by their position, velocity, acceleration (and possibly higher time derivatives, such as, jerk) without concern for the underlying dynamics/forces/causes.
2
votes
2answers
388 views
How do I find minimum constant deceleration so that object does not pass distance d in time t?
I'm working on a problem for an online judge site. I've boiled down the problem to this calculation: given a vehicle with an initial velocity $v$, how can one calculate the minimum constant ...
3
votes
1answer
305 views
How do I find the initial velocity in this problem?
An X-ray tube gives electrons constant acceleration over a distance of $20\text{ cm}$. If their final speed is $2.0\times 10^7\text{ m/s}$, what are the electrons' acceleration?
I know this ...
0
votes
0answers
231 views
Calculating the time given initial position, initial velocity, current position and constant acceleration [closed]
I'm trying to write a simple physics engine (a bit different than what is already out there) and I've got the following problem;
(For simplicity let's imagine this problem in one dimension;)
I have ...
0
votes
0answers
497 views
Finding the period and frequency for simple harmonic motion [closed]
A 1 lb weight is suspended from a spring. Let y give the deflection (in inches) of the weight from its static deflection position, where “up” is the positive direction for y. If the static ...
2
votes
1answer
113 views
Parabolic Motion
I was wondering if I was right about this simple problem:
A projectile is shot at an angle of 37.0° with the horizontal. The velocity of the projectile at its peak height is 16 m/s.
Then I was told ...
-2
votes
1answer
408 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 ...
2
votes
1answer
112 views
helium balloon tied to a car [closed]
A helium balloon is tied to the seat of a car. The doors and windows of the car is closed. If the car now starts moving, in which direction will the balloon move- front or back?
0
votes
2answers
88 views
Proof of $T=\sqrt{2y/a}$ in uniformaly accelerating object [closed]
Suppose that there is a object that does a y-axis-only free fall to ground. The initial distance from the ground is defined as $H$.
How does one prove that time the object takes to reach the ground ...
1
vote
2answers
303 views
Calculating force required to stop bungee jumper
Given that:
bungee jumper weighs 700N
jumps off from a height of 36m
needs to stop safely at 32m (4m above ground)
unstretched length of bungee cord is 25m
Whats the force required to stop the ...
0
votes
3answers
558 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 ...
3
votes
2answers
173 views
Find distance between turtles
I've been thinking about the following problem for some time now and was wondering if anyone could shed any light on it.
At time $t = 0$, turtle A sits at ...
0
votes
0answers
152 views
Basic Kinematics Question [closed]
I have a pretty basic problem regarding kinematics, but I'm new to physics. So, I'm having trouble with it. No, it is not homework. These are review problems, but this particular one is troubling me.
...
1
vote
1answer
137 views
Intercept a moving object
Object A can move at 50km/h, wants to intercept object B (currently $15^{\circ}$, east of north from A) moving at 26km/h, $40^{\circ}$ east of north. What angle should A take to intercept B? AB is ...
0
votes
2answers
969 views
Acceleration/tension of object. 1 on horizontal surface one hanging
A 5.00-kg object placed on a frictionless, horizontal
table is connected to a cable that passes over a pulley and
then is fastened to a hanging 9.00-kg object, as in Figure. Find
the ...
1
vote
1answer
543 views
Newton 2nd Law: Does vertical force (mass) affect the horizontal acceleration?
I learnt before that if 2 forces are perpendicular to each other, they should not affect each other. However in a recent experiment setup (asked in another question):
I believe the theoratical ...
2
votes
1answer
462 views
Determine acceleration from experiment (Newton 2nd Law)
I have done a physics experiment (setup below). And was asked to determine the experimental and theoretical acceleration.
The data I've got
Ok, am I right to say
Experimental acceleration ...
0
votes
0answers
50 views
How to calculate the necessary force to hold a bearing? [closed]
Assume I have a ball bearing which is holding radial load (gravity load) 100lb. The axial rotation has 500 lbf-in. How I can set up the equations to find out the necessary force to hold the bearing to ...
0
votes
2answers
284 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, ...
0
votes
1answer
126 views
Proving $t=(1+\sqrt{1+2hg/v^2 } ) (v/g)$ for a thrown ball
If we throw a ball from the hight point $h$ from the earth, with initial velocity $v’$, how to prove that the time it takes the ball to reach the earth is given by:
...
1
vote
1answer
60 views
Am I making the right assumption about a jump discontinuity in the acceleration?
A train heads from Station A to Station B, 4 km away. If the train begins at rest and ends at rest, and its maximum acceleration is 1.5 m/s^2 and maximum deceleration is -6 m/s^2, what's the least ...
0
votes
0answers
316 views
Velocity using spring contraction
I'm trying to determine the maximum final velocity of a body with which it contracts a spring until it touches the wall. It happens only with the presence of maximum energy. So, I've taken the kinetic ...
0
votes
3answers
354 views
Uniform Circular Motion
Why does the object not go inward, into the circle if the acceleration is inward? I think its because the velocity to outward? So they sort of cancel each other out? But if the speed is kept ...
0
votes
0answers
74 views
Jumping on a landing pad [closed]
I'm trying to make a character jump on a landing pad who stays above him. Here is the formula I've used (everything is pretty much self-explainable, maybe except character_MaxForce that is the total ...
2
votes
1answer
196 views
What is the longest distance that can be jumped after swinging from a rope?
In the movie Mission Impossible 3, the main character Ethan Hunt tries to enter a building in Shanghai by swing through the sky, as shown below:
The jump consists of 2 sections, the red part, which ...
0
votes
0answers
104 views
How do I solve this Kinematics question? [closed]
In 1987, Art Boileau won the Los Angeles Marathon, 26 miles and 285 yards, in 2h, 13 minutes and 9 seconds. At the 21-mile mark, Boileau had a 2.50 min lead on the second place winner, who later ...
0
votes
0answers
200 views
Projectile Motion
I know the angle at which a projectile is launched, how far it needs to go, and also the maximum height. How can I find the initial velocity needed (disregarding air resistance)?
Currently, I am ...
0
votes
2answers
838 views
How do you calculate angle of projection?
At what angle the projectile should throw with initial velocity v in order to reach distance d? discard the air resistance, only gravitation acts. So far I got the equations for horizontal and ...
0
votes
1answer
130 views
Power, Force Velocity
In any case, if the force and power is constant , does velocity also need to be constant? If no, can you tell me a case.
Further can this be extended for non-rigid bodies.
-1
votes
1answer
89 views
Simulating a car in an intersection
I'm somewhat confused. I want to simulate in real-time an intersection where cars have to turn left, right or go straight. What I have are 2 way points: One at the beginning of the intersection on ...
0
votes
2answers
255 views
Closest model for relationship between velocity and distance
Which is the model that best shows the relationship between velocity and distance:
$v \propto d$
$v \propto d^2$
$v^2 \propto d$
$v^2 \propto d^2$
What I think is from:
$$v=at \Rightarrow ...
4
votes
5answers
2k views
Why there is a 1/2 in kinetic energy formula? [duplicate]
Possible Duplicate:
Why is there a $\frac 1 2$ in $\frac 1 2 mv^2$?
Hèllo, I have a question about kinetic energy formula.
As you know, in kinetic energy formula, we have:
...
0
votes
2answers
722 views
Preventing a block from sliding on a frictionless inclined plane
I want to demonstrate what force $F$ you would have to exert on an inclined plane of angle $t$, mass $M$ to prevent a block on top of it with mass $m$ from sliding up or down the ramp. I worked out ...
3
votes
1answer
161 views
Lab observation correct? As distance decreases, velocity increases, stderr decreases
The experiment goes like this:
Allow a moving cart to move from the top of an incline plane ($x_0$) downwards. The time taken will be recorded by the picket fence (those things you see wired up). ...
1
vote
1answer
233 views
Kinematics - Find theta with Coefficient of Friction?
I recently found a problem that looked like this:
A box sits on a horizontal wooden ramp. The coefficient of static friction between the box and the ramp is ...
1
vote
3answers
338 views
Calculate kinematics of body movement from the set of spatial coordinates
Short intro
I have a set of 3D (x,y,z) spatial coordinates of arm movement obtained using motion capture system. The example set of such coordinates looks like this (rounded up):
...
0
votes
0answers
243 views
Basic kinematic equation [closed]
A truck moving with a speed of 18 m/s to a new speed of 13 m/s over a distance of 48 meters. How long did it take for the truck to break to its new speed, and what was the acceleration of the truck?
2
votes
2answers
420 views
Applying velocity Verlet algorithm
I want to implement a simple particules system using the velocity form of the Verlet algorithm as integrator.
Initial conditions at $t=0$ for a given particule $p$:
mass: $ m $
position: ...
3
votes
2answers
614 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
2answers
264 views
Maximum velocity allowed for motion profile with constant jerk
I´m trying to calculate what the maximum allowed velocity for a mechanical axis traveling towards a stop. The maximum velocity must be a secure speed so the axis have is able to stop in time.
I have:
...
2
votes
1answer
148 views
Relating angular and linear kinematics
In my physics book "University Physics", there is a chapter on relating linear and angular kinematics.
I understand the parts where it shows $v = r\omega$ and $a_{\text{tan}} = r\alpha$.
However in ...
0
votes
0answers
66 views
Kinematics equation [closed]
The motors of an electric train can give it an acceleration of 1 m/ sec square and the brakes can give a negative acceleration 3 metre/ second square. Find shortest time interval in which train can ...
0
votes
1answer
217 views
End position of movement factoring in deceleration
Ok I am hoping to apply this answer to a piece of software, but it uses physics to work out the result so I require some help in that department.
I will attempt to explain this the best I can.
I ...
0
votes
2answers
161 views
Human Kinematics:Does velocity or acceleration become zero at the moment of changing human limbs' direction of movement?
I need to know the answers to following questions about human kinematics. Can anyone kindly help me with it?
When human moves hand in one direction then suddenly or not changes direction of hand ...
2
votes
2answers
163 views
Ideal 2D Unicycle Kinematics
A particle is connected to a massive wheel by a rigid rod. The wheel can roll without slipping on a horizontal surface. The particle is free to rotate around the centre of the wheel.
I believe the ...
1
vote
2answers
103 views
Looking for the curve traced by a moving bicycle when its steering bar is fully rotated
I am looking for a curve traced by a moving bicycle when its steering bar is fully rotated either clockwise or anti-clockwise.
How to model it mathematically?
Is the curve a circle?
My attempt is ...
0
votes
0answers
389 views
Angle needed to launch a projectile to a given destination at a different height with given initial velocity
I need to calculate the angle required to launch a projectile from point A to point B on an uneven ground, given the parameters.
0nly gravity acts on the projectile – no air resistance.
Parameters ...
2
votes
2answers
877 views
Angles on swing sets
I'm building a swing set for my children. All of the designs I've seen involve building two A-frames and connecting them at the top with a crossbar/beam from which hang the swings. The A-frames are ...
2
votes
2answers
180 views
How do I adjust the kinematic equations to avoid reaching speeds faster than light?
I like some 'science' in my 'science fiction', so I started crunching out the kinematic equations for some of the scenarios my characters are getting involved in, and ran smack dab into an issue. ...
0
votes
3answers
229 views
The required energy to accelerate a particle from one velocity to another
Say I have a charged molecule running along a linear evacuated tube (so no wind resistance). In the laboratory frame, we can measure that the particle is moving at some speed $v_1$. Provided that ...
0
votes
2answers
94 views
Really basic mechanics and Galilean Relativity question
Consider two solid objects: A and B.
System 1:
A <----- B
10m/s
System 2:
A -----> B
10m/s
...
