Homework Statement
4 persons each with mass m stand out on the edge of the carousel that rotates with angular velocity W0. carousel has mass 4m, radius r and inertia I = 2mr^2. The 4 persons then go all the way to the center of the carousel.
Show that the final angular velocity W1 = 3W0
See...
I stumbled upon a 3-year old article from Wired that poses this question on rockets:
Suppose I have two rockets with a mass M and fuel mass m. Rocket A shoots all the fuel at once (again, like a nuclear propulsion engine) with a fuel speed of u and rocket B shoots two blobs of fuel—first a shot...
Homework Statement
The position of an object moving along the x-axis is given by x=a+bt^2, where a=8.5m,b=2.5 ms^-2, and t is measured in seconds. what is the average velocity between t=2.0 s and t= 4.0 s
Homework Equations
as we know, Vavg = xf-xi / tf-ti (f= final position and time and i=...
In discussion with my friend, we reached a conclusion that transformation formula of velosity v to another IFR moving V, i.e.
v'=\frac{v+V}{1+vV/c^2}
is valid even if v is hypothetical velocity,i,e,
v=\frac{x_2-x_1}{t_2-t_1}
v'=\frac{x'_2-x'_1}{t'_2-t'_1}
where interval of ##(t_1,x_1)\rightarrow...
I am in the process of making a program that visually shows an elliptical orbit over time. I wish to find the tangential velocity of the satellite in the elliptical orbit based on the variables that I know.
Here is what I know:
a) The angle relative to the right focus with 0 radians being the...
Homework Statement
What is Jack Sparrow's velocity when he falls down the ravine in Dead Man's Chest?
Homework Equations
P=MV?
The Attempt at a Solution
I don't know where to start. I think this is a projectile problem because he is in freefall when he falls down the ravine right? Or maybe it...
If Bernoulli's equation P + 1/2ρv2 + ρgh = constant, implying that pressure decreases as velocity increases, and the Venturi effect states that a1v1 = a2v, what resolves this apparent contradiction? The velocity slows as the cross sectional area increases, but a narrower pipe would have greater...
Hello all,
I was doing some behavioural modelling of the torque transfer characteristics of a belt drive system from the driver pulley to the driven pulley. While doing the same, i have tried to see how the angular velocity is getting transferred as well. I would explain my point with the...
I'm reading modern physics, Tipler 5th edition, pages 21 and 22, and I'm not understanding how the differentiation was done from the position to find the velocity.
Equation for position: x'= y(x - vt)
y is the gamma constant.
Then in the first step to find the velocity, a derivative was done...
Homework Statement
The velocity of a particle at a certain point is given as
\vec v=5(y\hat i - x\hat j). How to find the general equation of the path of the particle?
Homework Equations
Here, \frac{d\vec x}{dt}=5(y\hat i - x\hat j).
The Attempt at a Solution
As the velocity is not given as a...
Homework Statement
In the document below I need to try and find the angular velocity
I need help on part b
Homework Equations
F=ma
KE_Translational= 0.5mv^2
KE-Rotational= 0.5Iw^2
Assuming g=10m/s^2
The Attempt at a Solution
I have the answer key attached with the question but I am not sure...
In this derivation of the Ideal Rocket Equation (https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation#Most_popular_derivation), they use the fact that ##V_e = V - v_e##, or that the velocity of the exhaust in the observer frame ##V_e## is the velocity of the rocket ##V## minus the speed of...
Homework Statement
[/B]
We have water flowing in an open channel. A small tube is placed in the channel, and the water raises to a height "l" above the water surface. The distance from the water surface to point 1/2 (points are at same height) is d. At point 1 the fluid velocity is V1 and at...
Hello
When one calculates the speed of liberation of an object with respect to a star, one takes into account the force exerted by the star on the object. But not the force exerted by the object on the star. For small objects, this is valid. But what is the speed of release of a 1000 kg rocket...
I hope many here know about vortex tube and its application. I myself have done some study but were unable to find one answer. If we know the speed of the inlet fluid, then how can the angular velocity of the fluid during its rotational motion can be determined.
Morning!
I was performing some experiments about impulse and conservation of mechanical energy, and for that I was looking to good ways of measuring the velocity of a sphere under the action of a force. In free fall, having the height H it was falling along, I have used the formula v =...
Homework Statement
Homework Equations
a = v/t
p=mv(?)
The Attempt at a Solution
If an engine is turned on, that means that the ships are accelerating since the engine pushes back on air with a force and air pushes back to propel the ships forward, so I thought (A) would be the answer, even...
Homework Statement :[/B]In the arrangement shown in the figure, the two ends P and Q of the light unstrechable string move downward with uniform speed u as shown. The upward speed of the mass m is v. Then which of the following is correct:
A) v cos60°=u
B) 2v cos60=u
C) v =2ucos60
D) v= u...
I'm a surgeon, maths and physics study was a long time ago. I have been working on a project using an accelerometer and gyroscope.to.monitor hand movements during practice procedures.
I thought to represent my 3 axis acceleration as a vector and then subtract from this 1g, to compensate for...
I hear somewhere explanation
why kinetic energy is proportional to $v^2$ and not to $v^3$, for instance.
https://www.physicsforums.com/threads/quadratic-forms-and-kinetic-energy.826884/
I wish to find reference for this.
Now I find your thread with the same question and very similar answers...
Homework Statement
An ideal gas with molecules of mass m is contained in a cube with sides of area A. The pressure exerted by the gas on the top of the cube is P, and N molecules hit the top of the cube in a time
Δt. What is the average vertical component of the velocity of the gas...
Ive done some wind tunnel experiments for a wing design i made, the wind tunnel was set to 50% power and the incidence angle was increased from -2 to 14 at 2 deg increments, how do i calculate the velocity for each recording? I've done this before but I am just having a mental block on...
(I hope this post doesn't cross the border into the forbidden realm of quackery and speculation.) I have what seems like a simple question about Special Relativity but I haven’t seen it discussed anywhere, nor has anyone I've asked.
Does the nonlinearity of the Lorentz factor provide a way...
Homework Statement
Homework Equations
F = k(q1q1/r^2)
K = (mv^2)/2
The Attempt at a Solution
I got number 18 easy enough, number 19 seems simple but I'm not getting the right answer. I'm calculating Force exerted by each charge on the new charge using F = k(q1q1/r^2) for the three charges...
Homework Statement
If I want to find the difference in velocities of 2 objects A and B
We know the sum of their velocities is A + B
But but is the difference B - A
Why not A - B?
Homework Equations
This is from the equation of calculating restitution where
(greek letter) = (The difference in...
Homework Statement
Two spaceships pass each other. Spaceship A moves relative to nearby planet at velocity v1 , while spaceship B moves at velocity v2 relative to the planet . How fast does spaceship A moves relative to spaceship B.
Homework Equations
Velocity Transformation : v* =...
I stumbled upon these numbers on my test recently.
It is raelly basic stuff, but i want to know, what would actually happen if such thing happened in the real world.
We basically have a ball made of 20Kg of "person".
And it it accelerates at 1.8*10^5 m/s² for 1/30 of a second reaching 6000 m/s...
Homework Statement
A thin spherical shell is sliding with velocity ##v_0## on a table initial until friction eventually causes it to roll without slipping. Find its translational velocity when the it rolls without slipping as a fraction of ##v_0##.
Homework Equations
$$I=\frac{2}{3}MR^2$$...
I studied the vector analysis in Arfken and Weber's textbook : Mathematical Methods for Physicists 5th edition.
In this book they give the definition of vectors in N dimensions as the following:
The set of ##N## quantities ##V_{j}## is said to be the components of an N-dimensional vector ##V##...
Homework Statement
Butanol at a temperature of 28 C is pumped at a velocity of 14 m s-1 through a 100 mm diameter tube kept at a wall temperature of 90°C. The properties of butanol are given below.
Determine the convective heat transfer coefficient (you will find the appropriate correlation...
Homework Statement
Homework Equations
Emf=B l V V is (velocity)
F=QVB
The Attempt at a Solution
Emf=BLV
Work=QBLV
Force=BLV
how come V=Q/m. its not possible or is it?
When a P-N junction is in reverse bias, the drift velocity of the system increases, so why is there no current flow? Is the drift velocity not connected to the current?
Thanks in advance.
When the driver applies brakes its velocity starts decreasing and direction of acceleration will be same to the direction of velocity.
Is this statement True of False?
Please explain the true concept of this scenario. As far as I understand is that Velocity will start decreasing. But I am...
Let x = v_0\cos \alpha _0 t and y = y_0 + v_0 \sin \alpha _0 t - \tfrac{1}{2} gt^2, where
v_0 is speed at time t = 0,
\alpha _0 is the angle between positive x-axis and initial velocity vector (\alpha _0 \in (0, \pi/2)),
t time in seconds,
y_0 >0 the y coordinate at time t=0,
g acceleration...
In Lagrangian mechanics, both q(t) and dq/dt are treated as independent parameters. Similarly, in Hamiltonian mechanics q and p are treated as independent. How is this justified, considering you can derive the generalized velocity from the q(t) by just taking a time derivative. Does it have...
Homework Statement
A professional thrower projects a football straight up in the air.
1. Assuming there is no air drag on the football, find the speed of the football as a function of height as the ball goes up.
2. Assuming the air drag on the football varies linearly with speed, find the speed...
Homework Statement
The doorway in the previous question measures 1.06 m x 2.04 m, and the wind blows parallel to the wall surface at 3.89 m.s-1. Calculate the force pushing the curtains out of the doorway. The density of air is 1.29 kg.m-3.
Known data:
A = (1.06m)(2.04m) = 2.162 m^2
v(wind)...
I have read somewhere that the parallax method can be used to measure the distance to stars up to 400 light years away. I did a quick calculation and estimated that it means that our telescopes can resolve an angular movement of 8.15x10-3 arc seconds.
Taking the distance between the sun and the...
Hello!
Why does resistance to acceleration depend on both the velocity of the object as well as the direction of the force?
In circular motion, we can measure the centripetal force and centripetal acceleration, then we can calculate objects mass. Speed remains constant.
But we would get the...
Homework Statement
This isn't really a homework problem/question. I am just wondering if it is possible to calculate the vertical distance (dy) when the only given values are those of the horizontal distance (dx) and velocity (v). An example of this projectile-motion problem would be this:
A...
<Moderator's note: Moved from a technical forum and thus no template.>
I'm not sure how they got the extra (1/2)mv^2? My question is shown using pink font in the image below as well as my attempt.
Hello!
The equation for relativistic mass by special relativity tells us the relativistic mass for object in motion...but since inertia mass has same value as gravitational, does this formula also apply for gravitational mass?
Thank you!
Homework Statement
11.7 The motion of a particle is defined by the relation ##x = 2t^3 - 15t^2 + 24t + 4
where x is expressedin meters and t in seconds. Determine (a) when the velocity zero ,
(b) the position and the total distance traveled when the acceleration is zero
Homework EquationsThe...
Homework Statement
A loaded railroad car is rolling at a constant velocity when it couples with a spring and dashpot
bumber system. After the coupling, the motion of the car is defined by the relation
##x = 60e^{-4.8t} sin16t##, where x and t are expressed in millimeters and seconds...
Homework Statement
The Russian Mir space station had a mass of 130 tonnes and orbited Earth at an altitude of 480km with an orbital speed of 7621.4m/s. The diameter of Earth is 12 760 km.
a) What centripetal force was acting on it?
b) Find the value of the acceleration due to...
Homework Statement
Homework Equations
K = (1/2)mv2
U = mgh
W=Fd
Integration/Calculus
The Attempt at a Solution
I'm not sure what I should be doing for this question, if height changes how is it possible that velocity stays the same, according to the conservation of energy (frictionless wire)...
Homework Statement
Force of jet= A(r(t))4/3
A: constant determined by the fighter model in the class being considered and the drag force on the plane
r(t): the rate of fuel consumption as a function of time
Consider 3 possible situations for r(t):
1. when the rate is constant for the...
Homework Statement
Force of jet= A(r(t))4/3
A: constant determined by the fighter model in the class being considered and the drag force on the plane
r(t): the rate of fuel consumption as a function of time
Consider 3 possible situations for r(t):
1. when the rate is constant for the...
Hey people, this question was already asked here [https://www.physicsforums.com/threads/velocity-in-plane-polar-coordinates.795749/], but I just couldn't understand the answer given, so I was wondering if some of you could help me by explaining it again. I don't really get Equation (or...