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.

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4
votes
2answers
38 views

Is Torricelli's law “wrong” for big holes? - Tank draining problem

Consider a tank full of water with a constant cross-sectional area A1 placed vertically on the ground. Now someone drills a hole of an area A2 in the bottom of the tank, and the liquid starts escaping ...
3
votes
1answer
285 views

Acceleration: A ball sliding down the inside of a semicircular bowl

Edit: To clarify, this is a homework question. But I couldn't care less about getting the answer to this specific question as it's not even assigned yet. It looks interesting and I want to understand ...
0
votes
0answers
33 views

One extra conservation equation or angle relation for a relativistic collision

Edit: It seems that the derivation for the center of momentum frame was incorrect, due to the fact that the center of momentum velocity changes after the collision. This is also true for the ...
-4
votes
0answers
19 views

Kinematics Question - Motion in two dimensions [on hold]

Suppose there is a 11. 7 ft wide ditch with the approach roads at an single of 15 degree with the horizontal. If the length of bike is 5 ft and it leaves the road when the front part runs out of the ...
1
vote
2answers
84 views

Zero velocity and non-zero average acceleration

Can you have a zero velocity and nonzero average acceleration? I am confused with the word "average" here. If the question would be, "Can you have a zero velocity and nonzero acceleration?" my answer ...
0
votes
2answers
39 views

Best coordinate system for Projectile motion [on hold]

What is the best coordinate system for describing the projectile motion? Rectangular coordinate system or n-t(normal and tangential) coordinate system.
-2
votes
2answers
39 views

Finding the initial velocity of projectile [on hold]

What is the formula for calculating initial velocity of projectile using the conservation of energy given the mass, height, angle ?
0
votes
1answer
84 views

Projectile, air resistance and wind

So for my school project I am working on a projectile simulator and air resistance. So I have looked at this. Equations for an object moving linearly but with air resistance taken into account? ...
0
votes
1answer
137 views

What factors affect the velocity of an object moving down an inclined plane?

If you have a small toy car rolling down an wooden plank, what factors would increase or decrease the velocity of said car. In the experiment my team originally stated that adding mass to the car ...
1
vote
4answers
86 views

Acceleration of a particle moving along a straight line

If a particle moves along a straight line, then can we say that the acceleration should be zero? and if not, then why? If the equation of the motion is linear, then the velocity is constant and if ...
-3
votes
1answer
28 views

Non zero accetion, varying speed

Can an object have non zero acceleration without having varying speed? How? Can you explain with an example please.?
7
votes
1answer
271 views

Is it possible to determine particles' velocities from their crossings on a ring?

2 particles are constrained to move in a ring. Both particles begin moving at $t=0$ from $p=0$, each particle moving in the opposite direction of the other. It is known that they are moving at ...
0
votes
2answers
45 views

Derivation of $v=u+at$ [on hold]

I read the derivation of $v=u+at$ using integration. The steps are as follows - $$\frac{dv}{dt}=a dt$$ $$dv=adt$$ $$\int dv=\int a dt$$ $$\int dv=a\int dt$$ $$v=at+c$$ My questions are as follows - ...
1
vote
0answers
33 views

How Burmester's theory converts rotary motion of the crank to linear movement?

I have been studying the mechanism of Klann's Mechanical spider and there it was written that by Burmester's theory it converts rotary motion of the crank to linear movement. I tried searching but how ...
-5
votes
3answers
34 views

How to calculate meters per second speed when i have distance in meters and time in minutes [on hold]

It might be a simple formula but I want to confirm it so can you please tell me how can I find speed in meters per second when I have Distance = 7720298 meters and total time 320941.03 minutes. How ...
0
votes
0answers
21 views

How to calculate g-force of a vehicle in an accident through accelerometer values? [on hold]

i'm developing a crash notification android application.i want to calculate the g-force at the event of car crash.which is detected by the accelerometer of the smartphone.so far my code is as below, ...
0
votes
2answers
169 views

Ball flying towards me - Newton's third law is violated?

I was trying to answer the question of the flying ball here on the basis of Newtons third law and Momentum conservation. Here is what I have tried. Lets take $m_1$ (the ball) hits $m_2$ (the man). ...
0
votes
2answers
115 views

How does angular momentum affect the trajectory of a projectile?

I am thinking about a football thrown in a very tight, very fast spinning spiral. If the football is thrown upwards at a high angle, is it possible for the football to not turn over at the top of its ...
0
votes
2answers
34 views

String wrapping around a motionless cylinder

A particle is connected to the end of a thin, weightless string, which has its other end connected to the cylinder, in such a way that motion of the particle causes the string to wrap around the ...
3
votes
2answers
250 views

Projectile motion maximum distance to origin

Is there an elegant or easy way to derive the maximum distance from the origin to a point of the parabola created by projectile motion (assume initial position is the origin)? Other than ...
1
vote
3answers
485 views

Determine resultant velocity of an elastic particle-particle collision in 3d space

So I have two particles that have collided in 3 dimensional space. I want the particles to rebound off of each other in an elastic manner. How do I determine the resultant velocity vector if I know: ...
0
votes
3answers
32 views

Velocity and transfer of energy for a body in free fall

I just need to check if my understanding of the transfer of gravitational potential energy to kinetic energy is correct. Is anything wrong below? Say if a body were suspended at a height h above the ...
-2
votes
0answers
21 views

How can I figure out this uniform motion problem? [closed]

Julie drives 100 mi to Grandmother's house. On the way to Grandmother's, Julie drives half the distance at 40 mph, and the second half at 60 mph. On her return trip, she drives half the $time$ at 40 ...
-4
votes
0answers
40 views

Compute Speed of an Object when moving on a circular arc?

Consider the following figure: An iPhon is moving on a circular arc from point A to point B. The radius of the orbit is f. Consider the case that a men stands and holding his arm horizontal to the ...
1
vote
1answer
111 views

Magnitude of the average velocity vector (not the average speed)

Thank you ahead of time for taking to look at this. For this following problem we were given an answer however I am almost positive the given answer is wrong. It doesn't even make sense. So here is ...
0
votes
1answer
43 views

Finding the spring constant in SHM question [closed]

This question has got me confused, due to the fact that it says that the particle starts off at a negative amplitude, passes equilibrium, then has a positive velocity while moving back towards ...
0
votes
1answer
59 views

Which point in the graph does a parachute open?

The diagram represents speed-time for a sky diver. He falls freely from an aircraft then opens a parachute and later lands safely on the ground. At which point did the parachute fully open? ...
2
votes
2answers
77 views

A car with constant speed doing a turn

Let's say we have a car with four wheels and the center of the car has a speed of 50km/h. There is no friction or air resistance. If the car is moving straight each wheel will also have a speed of ...
1
vote
1answer
55 views

Solve $a(t) = g - \beta v(t)$ for $t$

If $g$ is the acceleration due to gravity and $\beta$ is a known value, solve for the time $t$ it takes an object to reach a given velocity if the acceleration of the object is given by ...
2
votes
4answers
358 views

What causes a car's velocity to follow the front wheels' direction?

I'm trying to simulate a car with correct physics models. In this example we let the car have a constant speed, and there are no forces (friction and drag) to slow down the speed. Here's a video that ...
8
votes
5answers
773 views

What's my weight when jumping on a bicycle from a higher to a lower ground?

Before I start defining the situation and asking a question, I'd like to make a few things clear: this is not a homework, merely a matter of personal interest and enthusiasm I am neither a ...
-2
votes
1answer
26 views

Which acceleration equations?

Which equation gives the most accurate answer? $$a=g \sin⁡ α-μg \cos⁡ α\\ a=s/t/t\\ a=2s/t^2 -(2v_0)/t$$ Because i get three different answers. The scenario is a box sliding down on an inclined ...
1
vote
3answers
142 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 ...
2
votes
4answers
4k views

Force applied to wheel in pure rolling motion at contact point with road

Suppose a wheel with radius $R$ is resting on a non-inclined surface. A torque $\tau$ is applied to the wheel center. In an attempt to prevent wheel from spinning, the ground applies a static friction ...
-1
votes
2answers
141 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
1answer
27 views

Car wheels in a turn [duplicate]

I know that when a car is taking a turn, the front 2 wheels trace out 2 arcs having the same centre. I also know that the steering angle for the outside wheel is more than that of the inner wheel to ...
1
vote
0answers
32 views

Is shaking a phone enough energy to charge a smartphone?

Is shaking a phone enough energy to charge a smartphone? For example I'd like to use some kind of power generator to charge smartphone's battery but I'm wondering if shaking (by hand, or motion when ...
0
votes
0answers
20 views

In Which Position A Co-passanger should Sit On A Turning Bike

Pardon me for this very basic mechanical science question. But I just want to clear my doubt it. Whenever I sit a behind someone on a bike I get confused when the the bike has to take a sharp turn. I ...
0
votes
0answers
15 views

Is there a “framerate” for the universe? [duplicate]

I've been wondering this for quite some time. I just can't wrap my head around the idea of truly continuous time. If time is truly infinitely divisible, then how can any object in the universe move? ...
80
votes
16answers
22k views

Why does kinetic energy increase quadratically, not linearly, with speed?

As Wikipedia says: [...] the kinetic energy of a non-rotating object of mass $m$ traveling at a speed $v$ is $mv^2/2$. Why does this not increase linearly with speed? Why does it take so much ...
4
votes
2answers
232 views

Question on particle decay process, conservation of energy

Why is $$\Sigma^0 \rightarrow \Lambda +\pi^0$$ not a possible process? Charge and baryon number both are conserved. There's no issue with strangeness that I can tell. The masses in $\frac{Mev}{c^2}$ ...
1
vote
1answer
54 views

Relativistic momentum of an electron

Suppose we have some interaction between a photon and an (initially) stationary electron, and we wished to find the final momentum of the electron. Should we solve this using conservation of momentum, ...
4
votes
4answers
338 views

Dodging paintballs

I was recently watching The Matrix, and was considering the speed at which one needs to move to literally dodge a projectile. Now, in real life, it is impossible to dodge bullets as such a feat would ...
-2
votes
0answers
14 views

Determining length of slope from angle and time down slope

I'm aware this is probably trivial, but I'm having a hard time with the following problem: "A child on a sled starts from rest at the top of a 15° slope. If the trip to the bottom takes 15.5 s how ...
0
votes
1answer
37 views

Force in a moving object that is not accelerating

If an object is traveling in a straight direction at a constant speed it has no acceleration, right? So if $F=ma$ and $a =0$ then force should equal 0. Does that mean a car traveling at a constant ...
0
votes
1answer
31 views

Question regarding the sail attached to a boat. [closed]

I came across a physics numerical in which the boat is travelling 45 degrees south-east. The direction of wind is towards north and the force that it exerts is constant force of 100 N on the sail. The ...
0
votes
2answers
40 views

A car is moving in a circular trajectory with radius R=20m. The equation of motion is : x(t) = 15 + 8t – t^2 [closed]

We have to find the distance the car has traveled after 3s. Actually this question came up in an important exam, and the answer was: L=x(3)-x(0) But I think this is the answer for displacement, ...
1
vote
2answers
43 views

Time taken by a stone to reach the ground is independent of point of dropping

A balloon is rising. A stone is dropped and the stone takes $\frac{2u}{g}$ to reach ground (Nothing is known about $u$ and $g$ is the acceleration due to gravity), irrespective if the point of ...
0
votes
3answers
149 views

Animating an Acceleration Vector - Acceleration of object on a crested path in gravitational field

So I was reading in Chapter 3 of my textbook, Sears & Zemanksky's University Physics with Modern Physics by Young and Freedman, 13th Edition, and the discussion took us to a definition of the ...
3
votes
3answers
579 views

Does a heavy body move with the slightest force on a frictionless surface?

If I apply horizontal force on a body resting on the ground, my force will be opposed by the frictional force and the body will accelerate at the point where my force exceeds the force of friction = ...