What is Work done: Definition and 1000 Discussions
In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, it is often represented as the product of force and displacement. A force is said to do positive work if (when applied) it has a component in the direction of the displacement of the point of application. A force does negative work if it has a component opposite to the direction of the displacement at the point of application of the force.
For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). When the force F is constant and the angle between the force and the displacement s is θ, then the work done is given by:
W
=
F
s
cos
θ
{\displaystyle W=Fs\cos {\theta }}
Work is a scalar quantity, so it has only magnitude and no direction. Work transfers energy from one place to another, or one form to another. The SI unit of work is the joule (J), the same unit as for energy.
Homework Statement
Show that the net work done by the otto engine per cycle is
Cv(Tc - Tb)(1 - Ta/Tb)
PV diagram:
[PLAIN]http://www.antonine-education.co.uk/physics_a2/options/module_7/topic_4/Otto_indic.gif
Homework Equations
Work done by a kmole of gas expanding irreversibly and...
Homework Statement
A right circular cone has vertex down and is 10 feet tall with base radius 5 feet. The cone is filled with a fluid having varying density. The density varies linearly with distance to the top. Here "varies linearly" means the quantities are related by an equation of at most...
Homework Statement
A loaded sled is pulled by means of rope that makes an angle of 45 with the horizontal. If the mass of the sled is 60 kg and the coefficient of friction is .0200, how much work is done in pulling the sled at constant velocity along a level road for a distance of 1.00 km...
Hi,
I was thinking about the isothermal and adiabatic expansions in the Carnot Cycle and I was wondering:
In these processes, the gas is doing work. In the adiabatic change, the pressure (force), acts over a distance (expansion) transferring energy (Kinetic Energy) - but this is an adiabatic...
Find the work done by the force field F= 3yi - x^2j
in moving a particle along the curve y=x^(1/2) from (1,1) to (4,2)
so i parameterize and get x=1+3t, y= 1+t
so
3(1+t)-(1+t)^2
then take the derivative of x and y and multiple to ge
9(1+t)-(1+t)^2
and i integrate that from...
Hi all,
Speed is a ratio of the distance traveled per unit time. But what then is work done and moments?
For example, work done is force multiplied by the distance traveled in the direction of the force. But how would you explain the rationale of multiplying these two quantities?
As...
Homework Statement
0.5 m3 of air is located in a vessel. Their temperature is T1=0oC and the pressure is p=3·105. What work will be done when heating the gas with constant pressure (isobaric process) to T2=100oC?
Homework Equations
I was unable to find any equation regarding to the...
10N force acting in the direction of the vector (1, 1) moves an object from P (-2, 1) to Q (5, 6), calculate the work done.
The Attempt at a Solution
I can do this question correctly except I only know how to do it using decimals but the answer is in exact values of 60√2J. I can't figure out...
Hi All
I'd like to know how I could calculate the work done by a distributed force on a string.
Let's say the force at a point x at a time t is given by
F(x,t).
Now the instantaneous amplitude of the string is given by y(x,t), say
I think that the work done by the force in...
Homework Statement
A 0.75 sphere is dropped through a tall column of liquid. When the sphere has fallen a distance of 2.0 m, it is observed t have a velocity of 2.5 m/s. How much work was done by the frictional viscosity of the liquid?
PLEASE EXPLAIN-- I really would like to understand this...
Homework Statement
Find the work done by the force field F in moving an object from P to Q.
F(x,y,z)=10y^(3/2)i+15x\sqrt{y}j
P(1,1), Q(2,9)Homework Equations
W = \intF dot drThe Attempt at a Solution
I have no clue how to do it
Figure 20-29 shows a reversible cycle through which 1.00 mol of a monatomic ideal gas is taken. Assume that p = 2p0, V = 2V0, p0 = 1.13*10^5 Pa, and V0 = 0.0235 m^3.
Fig. 20-29 http://s1142.photobucket.com/albums/n603/bdoneski/?action=view¤t=hrw7_20-29.gif"
(a) Calculate the work done...
Homework Statement 1 mole of an ideal gas is at 9 atm pressure,
occupies 1 L and has an internal energy of
474 J. The gas is first cooled at constant
volume until its pressure is 1 atm. It is then
allowed to expand at constant pressure until
its volume is 7 L with an internal energy of
766...
Hi guys, :smile:
Work Done = Force x Distance x cos of Theta - the angle between the Force and the Displacement Vector / direction of motion
In Circular motion I know the force but I am given velocity. In order to prove that no work is done is it correct to say the following:
If we have two...
Hi :smile:
So, let's go straight to the point: a = v - u / t
Kinetic Energy: 1/2 mv2
Ok, I understand that a acceleration, a change in velocity, will change the Kinetic Energy since v is part of the Kinetic energy equation.
But acceleration is not simply a change in velocity. It is the rate...
Homework Statement
An ideal gas follows the three-part process shown in the figure.
At the completion of one full cycle, find the net work done by the system.
Homework Equations
W=P*deltaV; Total Work = Wab+Wbc+Wca
A=1/2bh
The Attempt at a Solution
Work done from C to A is zero, because...
Homework Statement
http://img26.imageshack.us/i/1113001.jpg/
#11
Homework Equations
C = 2πr
w=fd
The Attempt at a Solution
it travels from point 1 to 2 so its half a circle so the distance is πR.
πRF = w
so i would guess its D.
but the answer is A) zero. i do not know why...
Homework Statement
When a volume 10^-3 m^3 of a certain gas at a pressure of 1 atm undergoes a reversible adiabatic compression to half its volume, its pressure rises by a factor of three. The internal energy of the gas is given by E=3PV, where P is the pressure and V is the volume. By making...
Homework Statement
The pulley in the illustration is a uniform disk of mass 2.40 kg and radius 0.220 m. The block applies a constant torque to the pulley, which is free to rotate without friction, resulting in an angular acceleration of magnitude 0.180 rad/s2 for the pulley. As the block falls...
Homework Statement
In a cylindrical region of radius R, there exists a time varying magnetic field B such that dB/dt=k(>0) . A charged particle having charge q is placed at the point P at a distance d (> R) from its centre O. Now, the particle is moved in the direction perpendicular to OP (see...
Homework Statement
How much work is done by a force= (2x)i N + (3)j N with x in meters, that moves a particle from a position (initial) = (2m)i + (3m)j to a position (final) = (-4m)i + (-3m)j?
Answer:
- 6 J
Homework Equations
Work = integral of Force
The Attempt at a Solution...
Homework Statement
A 230 kg crate hangs from the end of a rope of length L = 12.0 m. You push horizontally on the crate with a varying force to move it distance d = 4.00 m to the side (Fig. 7-43). (a) What is the magnitude of when the crate is in this final position?
Figure...
Homework Statement
A coin slides over a frictionless plane and across an xy coordinate system from the origin to a point with xy coordinates (2.2 m, 6.1 m) while a constant force acts on it. The force has magnitude 8.2 N and is directed at a counterclockwise angle of 108° from the positive...
Homework Statement
A tank of water is 3m long and has a triangular cross section of height 1m and width at the top of 1m. How much work is done pumping the water to the top of the tank? The density of water is 1000kg/m3 and the gravitational constant g has value g m/s2
Homework Equations...
An electric elevator with a motor at the top has a cable weight 4.5 lb/ft. When the car is at the first floor, 198 ft of cable are paid out, and effectively 0 ft are out when the car is at the top floor. How much work does the motor do just lifting the cable when it takes the car from the first...
Hello,
Was wondering if anybody could help with the following question as I am struggling, and this area is not my strong point. Note this is not homework purely self-study, out of curiosity to help me understand the subject area in more detail.
In each minute a pump draws 2.4m^3 of water...
Homework Statement
How much work is done against gravity to fire a 7.2*10^2 kg weather monitor 120km into the air.
Homework Equations
Mass Earth = 5.98*10^24kg
radius of Earth = 6.38 * 10^6 m
Eg = -GMm/r
delta Eg = Eg 2 - Eg 1
The Attempt at a Solution
Eg1= -[(6.67*10^...
Homework Statement
Imagine a block with mass m being pulled up a frictionless incline with upward angle theta by a rope with tension force T. The mass is pulled until another point of rest at a point distance d away from the original point (with d measured on the incline) and h measured on the...
Homework Statement
There's a cone with height 12 feet and radius 4 feet. It is filled with water to a depth of 9 feet. Find the work required to pump the water over the top. The density of water is 62.4lbs/ft^3
work=force*distance & force=volume*density
The Attempt at a Solution...
Homework Statement
a cyclist rides up a steady slope for a distance of 1200m and rises 90m vertically as a result. the total mass of rider + cycle is 80kg
a) assume a drag force of 10N opposing the motion(due to air resistance and friction), what Total Work must be output by the rider for...
Homework Statement
An object of mass 1200 kg rests at a height of 95 m above the ground on a roller coaster. After a series of inclined planes, repeately reaching a height of zero, (bumps and drops of the roller coaster) the roller coaster lays horizontal on the ground (height zero) for 7 m...
Homework Statement
In the temperature range 310K and 330K the pressure of a non ideal gas is related to volume V and temperature T by P=(24.9 J/K) T/V− (0.00662 J/K^2)T^2/V. How much work is done by the gas if it's temperature is raised from 310K to 320K whilst pressure held constant...
Homework Statement
A block of mass 1.60 kg is pulled up a rough 30 degree incline at constant speed by a string parallel to the surface. The friction force on the block is 7.00 N. The incline is 4.00 m long and 2.00 m high.
(1) How much gravitational potential energy did the block gain...
Homework Statement
A block is being slid along a rough surface by a force of 94.6 N forming an upward angle with the horizontal of 29 degrees. The mass of the block is 18.7 kg. It is displaced 70.6 m, and the coefficient of friction is .186
what is the total work done by the force...
Our local YMCA is putting on an indoor triathlon and I am trying to come up with a formula to help them determine the winner of the cycle segment.
The indoor triathlon consists of a 10 minute pool swim, a 20 minute cycle on an indoor, stationary bike, and a 20 minute run on the treadmill. The...
Homework Statement
Two blocks are connected by a very light string passing over a massless and frictionless pulley (Figure ). The 20.0-N block moves 75.0cm to the right and the 12.0-N block moves 75.0cm downward. Find the total work done on 20.0-N block if there is no friction between the...
Hi,
In deriving the equation for adiabats : V^{\gamma}P = C. It is assumed that the work done during the process is W = -P \Delta V.
But calculating the work done from V^{\gamma}P = C we obtain:
W = \frac{C}{1-\gamma}\left[ V^{1-\gamma}_{f} - V^{1-\gamma}_{i} \right] .
Also, i believe to...
Homework Statement
A 0.245 kg ball is thrown straight up from 2.20 m above the ground. Its initial vertical speed is 12.40 m/s. A short time later, it hits the ground. Calculate the total work done by the force of gravity during that time.
Homework Equations
1/2m(v initial)2 + mg(h...
Homework Statement
The floor of a basement in a house is 3.2m blow the grade of a window sill. If the Basement has flooded to a depth of 0.44m and the basement is 10.3m by 18.4m. If the water leaves the pipe at 2.4m/s, how much work was done by the pump. (Density of water is 1000 kg/m^3)...
Homework Statement
A box, whose weight is 182 kg, is drawn with constant speed 21 m along a horizontal concrete floor. The kinetic friction between the box and the floor is 0.58.
(acceleration due to gravity, g = 9,81 m/s2).
Homework Equations
Calculate the work done when the box is drawn...
I am having a little trouble understanding this and I was wondering if I could get some help.
I understand that work done at constant volume is zero because since the volume isn't changing, there is no movement on the boundaries and therefore no work. But it isn't coming out mathematically...
Homework Statement
A 12 kg brick moves along an x axis. Its acceleration as a function of its position is shown in Fig. 7-37. What is the net work performed on the brick by the force causing the acceleration as the brick moves from x = 0 to x = 5.2 m...
1. Homework Statement [/b]
A block of weight mg sits on an inclined plane as shown. A force of magnitude F is applied to pull the block up the incline at constant speed. The coefficient of kinetic friction between the plane and the block is Mu.
What is the total work done on the block by the...
Hello,
I have a question that should be pretty simple, but I can struggling to understand:
What determines the amount of work done in lifting a ball from one to two metres above the ground?
I know that W=Fd and F=ma , so I would assume that the work done would equal m*a*d.
Something...
A force acts on a particle of 1.6kg mass, the force is related to the position of the particle by F=0.5x^{3}
Find the work done by the force as the particle moves from x=3.8 m to x=2.0 m.
By plugging each value of x into the force equation I get that:
F at 3.8 m = 27.436 N
F at 2.0 m =...
The problem states: how much work is done in moving an electron from a distance of 1nm to a distance of 10nm away from a hydrogen nucleus?
My attempt at the problem is using the W=\DeltaU=q\DeltaV. With this equation I would get a positive work. However, when I reason through the question, I...
Homework Statement
A paddle turns at 28.0 rad/s and exerts a torque of 16.0 Nm to stir the paint.
Internal energy increase of 12.5kJ causes the temperature of the paint to increase by 1.00K.
If there where no heat flow between the paint and the surroundings, what is the change in temperature...
Homework Statement
A sack of flour (mass m) can slide along a parabolic track i the vertical plane defined by y = \gammax2 The coefficient of (dynamic) friction is \mu. You move this sack from x = 0 to x = x1 along the track by pulling it with a horizontal force F (you do this quasi-statically...
Homework Statement
A box is dragged 16 m across a level floor by a 75N force at an angle of 35 degrees to the floor . It is then dragged by the same force 8m up a ramp inclined at an angle of 20 degrees to the floor. Determine the total work done by the force. Homework Equations
W= F(d)Cosθ...