In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body when decelerating from its current speed to a state of rest.
In classical mechanics, the kinetic energy of a non-rotating object of mass m traveling at a speed v is
1
2
m
v
2
{\displaystyle {\begin{smallmatrix}{\frac {1}{2}}mv^{2}\end{smallmatrix}}}
. In relativistic mechanics, this is a good approximation only when v is much less than the speed of light.
The standard unit of kinetic energy is the joule, while the English unit of kinetic energy is the foot-pound.
Homework Statement
"A rope is used to pull a ##\frac{357}{100}kg## block at constant speed ##\frac{203}{50}m## across a horizontal floor. The force on the block from the rope is ##\frac{768}{100}N## and directed ##15°## above the horizontal. What are (a) the work done by the rope's force, (b)...
Homework Statement
A wooden toy mouse of mass (m) is attached to a spring with constant (k) and suspended vertically as shown below. The toy is released at the point the spring is unstretched at position x = +A, passes through equilibrium at x = 0 and the spring’s maximum extension occurs at x...
How should I look at the problem at stopping a moving object with the following conditions
1) mass m and speed v
2) 0.5 m and 2v
3)0.5m and sqrt 2 v
Simple math tells me the number 2 would require more energy to stop it. I can relate to energy better in terms of how to stop a moving mass...
Homework Statement
Ball 1 has an inertia of 0.500 kg and ball 2 has an inertia of 0.600 kg . Ball 1 is moving away from you at 5.0 m/s, and you decide to throw ball 2 at it to make it go faster. The balls collide head-on, and the coefficient of restitution for the collision is 0.95.
Part A)How...
I ran into the following problem, and stuck for a couple of days now.
I have a solid body, rigid and and has uniform density. Its mass M, the location of the center of gravity x_M, y_M, z_M and its inertia matrix is known:
Jx Jxy Jxz
Jyx Jyy Jyz
Jzx Jzy Jz
I have to write an algorithm...
1. The problem statemees and given/known data
A ball has a potential energy of 200J. Once the ball reached the ground, it's kinetic energy was 175J. Is this possible and does this defy the conservation of energy?
Homework Equations
KE = PE
The Attempt at a Solution
I am not sure. Being in high...
Homework Statement
Homework Equations
ΔKE=W+FcosΘd
KE=.5mv^2
Final Vel^2=initial Velocity^2+2ax
The Attempt at a Solution
So calculate the force at x=2.6 to -5.356N, set 2.6(-5.356)=1.3Vf^2-1.3(0^2) which seemed to prove a problem as the square of the final velocity was negative, but just...
Homework Statement
I need to accommodate a dashpot in an intentionally simple work-kinetic energy analysis method. For example, for a box being dragged up a ramp via a rope while attached to a spring, I can deal with the work done by gravity, rope tension, spring force, and friction via the...
In the tablecloth trick, if we pull the tablecloth with a great force, the objects on it will stay on the table. But, if we pull it gently, the objects on it will still get along with the cloth movement.
I know that if the force exceeds the maximum value of static friction, the objects will...
Hi, I'm a high school science teacher. Most textbooks classify EM radiation as kinetic energy. But this doesn't seem right to me. As a photon is massless it's hard to see how it can have kinetic energy which is 1/2 mv^2.
It could be said that it has energy hf and therefore mass hf/c^2. Then its...
When I learned about operators, I learned <x> = ∫ Ψ* x Ψ dx, <p> = ∫ Ψ* (ħ/i ∂/∂x) Ψ dx. The book then told me the kinetic energy operator
T = p2/2m = -ħ2/2m (∂2/∂x2)
I am just think that why isn't it -ħ2/2m (∂/∂x)2
Put in other words, why isn't it the square of the derivative, but...
1. Problem Statement:
A worker lifts a heavy crate vertically 1.0 m in 2.0 s. If she lifts the same crate the same distance in 1.0 s, the work was done by her is
A
the same.
B
two times as great.
C
half as great.
D
four times as great.
E
one-fourth as great...
Homework Statement
I really don't have a homework question just a thought. Is rest energy "maximum energy" for a particle? As to say a particle at rest has a given energy, so when it is in motion it transfers some mass energy to kinetic energy, where both the mass and kinetic energy together...
Hi,
I am looking for a video helping intuition on pressure, in the context of kinetic theory of gases.
I remember seeing a video where someone poured a bucketful of little hard balls (lead sinkers for fishing?) onto an electronic scales (a dynamometer, really) showing that this corresponds to...
Homework Statement
"In Fig. 8-33, a runaway truck with failed brakes is moving downgrade at ##130\frac{km}{h}## just before the driver steers the truck up a friction-less emergency escape ramp with an inclination of ##θ=15°##. The truck's mass is ##1.2⋅10^4kg##. What minimum length L must the...
Homework Statement
Show that the largest possible change in the kinetic energy , ##\Delta E_{kin}##, of a particle of mass ##m## running into another particle of mass ##M## at rest in the lab coordinate system is
\Delta E_{kin} = \frac{-4AE_{kin}}{(1+A)^{2}}, where ##A = \frac{M}{m}##...
Homework Statement
Consider the motion of charged particles, in one dimension only, in
the presence of an electric potential V ( x). Show, by direct substitution,
that a function of the form
f=f(1/mv^2 + qV)
is a solution of the Boltzmann equation under steady-state conditions.
Homework...
Homework Statement
The ammonia molecule (NH3) has a dipole moment of 5.0×10−30C⋅m. Ammonia molecules in the gas phase are placed in a uniform electric field E⃗ with magnitude 1.3×106 N/C .
Part A:
What is the change in electric potential energy when the dipole moment of a molecule changes...
Hey guys, this question has boggled my mind not because I don't know how to approach it but apparently the method I'm using is incorrect!
Question
A cannonball with a mass of 150 kg is fired from a cannon. The cannonball leaves the cannon with 447.9 kJ of kinetic energy. The cannon makes an...
Homework Statement
If the speed of a vehicle increases by 2m/s then it's kinetic energy is doubled. Find out the original speed of the vehicle
Homework Equations
1/2(mv^2)
The Attempt at a Solution
First find out both KE(kinetic energy) taking u(initial vel.)
And v(final vel.) And mass as m...
In an inelastic collision is the change in kinetic energy equal to the difference of final and initial momentum if one of the objects is initially at rest? For example:
m1v = (m1+m2)Vf -----> 0 = (m1+m2)Vf - m1v1
1/2(m1+m2)Vf^2 - 1/2m1v^2 = (m1+m2)Vf - m1v1
Or totally wrong? Thanks!
Homework Statement
A block of mass ## M_1 ## is on an inclined plane (the plane is inclined at 30 degrees), and is attached with a light cord over a light, frictionless pulley to another mass ## M_2 ##. ## M_1 ## is fixed at 5.00kg, and ## M_2 ## can be varied.
When ## M_2 = 3.20 kg ##, ##...
Homework Statement
Homework Equations
F=m*a
ΣF(n-direction)= m*a(n)= m*(v^2/ρ)
∑F(t-direction)= m*a(t)\
Ffriction= Fn*coefficient(of friction)
The Attempt at a Solution
So I tried solving this question and apperently it is way easier than I thought.
So I thought the kinetic friction has a...
KE is proportional to v^2. In a gravitational field KE=1/2 m*v^2.
It's easy to find mathematically Work=Fd=mad=m(v/t)(v*t)=m*v^2.
But how to visualize it or get an intuitively "feel" for this v^2 relationship?
A spring of spring constant k sits on a frictionless horizontal table, one end of the spring is attached to a wall the other end to a block of mass M= 2kg, also resting on the frictionless table. Another block of mass m=450g moving at a speed of 7m/s collides in-elastically with the block of...
1.e problem statement, all variables and given/known data
Two positrons and two protons are kept on the four corners of a square of side a. Positrons are kept at vertices A and C and protons are kept at B and D. let q denote the charge on both positron as well as the proton. So what is the...
A 6.0kg metal ball moving at 4.0m/s hits a 6.0kg clay ball at rest and sticks to it. The two move at 2.0m/s.
a. calculate the kinetic energy of the metal ball before it hits the clay ball.
b. calculate the kinetic energy of the metal ball after it hits the clay ball.
c. calculate the kinetic...
Homework Statement
Given, force of constant magnitude, which is always perpendicular to the velocity of the particle & the motion takes place in a plane. What happens to its kinetic energy? Explain.
Homework Equations
Work energy theorem
The Attempt at a Solution
According to work energy...
Homework Statement
Calculate the kinetic energy of CO, CO2, and SO3 at 276 K .
Homework Equations
KE = (3/2) RT
KE= (1/2)(mass)(velocity)^2
The Attempt at a Solution
[/B]
For CO:
First attempt: KE=(3/2)(RT)=(3/2)(8.314 J/mol-K)(276K) = 3441.996 -- So that's wrong
Second attempt:
Relative...
As we all know, for the most part, the kinetic friction force is, for the most part, constant. After moving my cup across my table, this thought crossed my mind. If I move my cup across the table with a constant speed, then the force I'm applying must be equal to the kinetic friction force...
Homework Statement
I have a table that needs to be filled out. In each column, potential and kinetic energy are given, but height and velocity are left blank. Ex: PE = 20 J, KE = 0 J, h = ?, V = ?
Homework Equations
KE = 1/2mv^2
U = mgh
The Attempt at a Solution
I'm totally stumped. How can I...
Homework Statement
Hi I know my picture has 2 problems, but let's just focus on the first problem parts a and b.
So for part a it ask for the final frequency after the ant landed, and part b is the kinetic energy difference. Basically the
ant=.01kg, diameter of cylinder is .115m,
the weight of...
Hello,
Throwing out a question to see if anyone has some insight.
The kinetic salt effect describes the variation of the rate constant of a reaction with respect to the ionic strength of the solution. The mathematical relationship considers the ionic strength (molality/ion charges) of the...
Homework Statement
Why is there more heat and sound energy produced with a larger collision?
Homework EquationsThe Attempt at a Solution
Honestly no clue. I would really appreciate any help! Any videos would also help!
Hi there,
I have a problem to solve in Cosmology which says:
"Write the formulas for the quantum kinetic energy of neutrons, protons and electrons as well as the formula for the gravitational energy for a neutron star that is comprised of free neutrons, protons and electrons in a ratio of Nn ...
Is there a threshold of maximum kinetic energy lost when kinetic energy is transferred between two objects through collision?
I just cannot find any information on this, any help would be VERY much appreciated.
If i compress water to 60 ksi, and push it through a 0.015" sharp orifice, then i have another orifice 2 feet before that sudden open to 0.015", what is the velocity of the stream from each orifice?
Homework Statement
Ok I have the answers to parts a and b, which I am 100% confident in since they are simple computations
Question is in attachement
a)74.9 rad/s
b)168.08 rad
My issue comes in when I have to get parts c
The mass of the cylinder is 8.7kg,
its diameter is .18m,
its .35m long...
Homework Statement
A 0.26-kg block on a horizontal frictionless surface is attached to an ideal massless spring whose spring constant is 190 N/m. The block is pulled from its equilibrium position at x = 0.00 m to a displacement x = +0.080 m and is released from rest. The block then executes...
I'm writing a story in a fantasy universe, but for a certain aspect, I need realism. The densest summation of the questions I have are this:
What would a single rod of kinetic bombardment look like being shot into the dense sand of a desert, visually?
What angle of shot would be easiest to pull...
Homework Statement
According to the kinetic molecular theory:
as the distance between the molecules increases, the temperature of a material decreasesthe rise in temperature of a material occurs because the molecules lose kinetic energywhen the molecules within a gas collide they lose energy...
Homework Statement
Homework Equations
i) F=ma=mv/t
ii) E=mv2/2
The Attempt at a Solution
Now based on equation 1 , I have concluded that the velocity gained is inversely proportional to m, and that so is the kinetic energy , I have seen otherwise.[/B]
Homework Statement
Sam, whose mass is 75 kg, stands at the top of a 12-m-high, 100-m-long snow-covered slope. His skis have a coefficient of kinetic friction on snow of 0.07. If he uses his poles to get started, then glides down, what is his speed at the bottom?
Homework Equations
v =...
Lets say that there is a rectangular box on a horizontal surface, with no air resistance on it. If the applied force required to get the object moving is greater than the static friction, Fa>Us* Fn, then the object starts moving. However, the Static Friction is almost always greater than the...
Consider the internal energy of a gas and solid (different materials) both at the same temperature, which material has the larger potential energy and why? Do they also both have the same kinetic energy? Finally is the definition of temperature as the average kinetic energy of the particles only...
Stefan throws a baseball with the speed of 140 km/ℎ. The ball goes obviously in goal, but it bounces back out of the net with a speed of 50 km/ℎ. What percentage of
the kinetic energy remaining after contact with the net?
A block of mass 9kg is initially at rest at the top of an inclined plane of ramp length 4m.
-Assuming that the plane is frictionless, calculate the speed of the block at the bottom of the plane.
-Now instead assume the a frictionless force of Ffr = 2 Newtons opposes the motion of the block...
In chromatography, the upper portion of the moving water solvent has more kinetic energy, than the lower portion of the moving water solvent because the lower portion of water molecules have to face more obstacles in the way because of the absorbed water molecules. Is it true?