Share
Explore BrainMass

Work

A force is said to do work on an object when the body it acts on has a displacement of the point of application. Force does work when it results in movement. The SI unit of work is a newton-metre or joule (J).

Work was introduced in 1826 by a French mathematician Gaspard-Gustave Coriolis. [1] He described work as the “weight lifted through a height”. This was based on the early steam engines ability to life buckets of water out of flooded mines.

Work done by a constant force of magnitude F on a point that moves a displacement d is:

W=Fd

For moving objects, the quantity of work/time is calculated as a distance/time, or velocity. Thus at any instant, the rate of work done by a force is the scalar product of the force and the velocity vector of the point of application. The small amount of work done over an instant of time is calculated as:

δW=F*vδt

To calculate the work over a distance can be calculated by integration. The derivation leads to:

W=Fd cosθ

Oscillations near the equator.

Consider (unrealistically) a perfectly spherical rotating planet whose g value is constant over the surface. A bead lies on a frictionless wire that lies in the north-south direction across the equator. The wire takes the form of an arc of a circle; all points are the same distance from the center of the earth. The bead is r

Understanding Work, Energy & Power

Explain the concept of Work, Energy and Power. Also describe various types of mechanical energy compared to kinetic energy and potential energy and inter relation between them.

Work of Magnetic Field

The magnetic field can store energy, but it can do no work. Therefore, another agency must be responsible for doing the work that puts the energy into the magnetic field. In order for the energy in the field to be reduced to zero, work must be done. Explain where the energy goes when the B field collapses. What possible agen

Solving Basic Physics Problems

1) If you do 100 J of work to elevate a bucket of water, what is its gravitational energy relative to its starting position? 2) Suppose two blocks of ice are heading towards each other. Block A has a mass of 4.24 kg and is traveling at 2.24 m/s. Block B has a mass of 4.42 kg and is traveling at 2.24 m/s in the opposite directio

Velocity After Impact

Two bowling balls are rolling toward each other. Ball A has a mass of 5 KG. Ball B has a mass of 6 KG. Ball A is traveling at 3 m/s. Ball B is traveling at 6 m/s. After impact, Ball B continues to move in its current direction at 1 m/s. What is Ball A's velocity after impact?

Hydraulic Cylinders

Explain how power is created using hydraulics and how a little cylinder on the tractor can raise or lower extreme amounts of implement weight. Explain the system including parts and functions.

Force Field Exercise

I need perfect step by step solution please. A force is given by: (vector)F(x, y, z) = (yz)x(^) + (xz)y(^) + (yx)z(^). a. Find the work done by this force when a particle is taken from (0, 0, 2) to (2, 4, -3). Can you choose any path, or does the answer depend on the path? b. Can a potential energy function be specified

Block of mass 2.5 kg is placed against a compressed spring

Please refer to attachments for details. 6. A block of mass 2.5 kg is placed against a compressed spring (k = 2900 N/m) at the bottom of an inclined plane, as shown. When the spring is released the block is projected up the incline and the spring expands by 14 cm to its normal length. Calculate the maximum distance travele

Physics Kinematics Multiple Choice

Sample Question: To cause a 25 kg object to experience an acceleration of 2 m/s2 the net force that needs to be applied to the object is Please see attached to view the rest of the multiple choice questions.

13

A 90kg box is pushed by a horizontal force F at constant speed up a ramp inclined at 28 degrees. Determine magnitude of applied force a) when ramp is frictionless b) when coefficient of kinetic friction is .18

Speed of a Projected Stone

A stone is projected at a cliff of height h with an initial speed of 40.0 m/s, directed 60.0° above the horizontal. The stone hits the top of the cliff 6.10 s after it is launched. Calculate: a. the maximum altitude of the stone. b. the height of the cliff. c. the stone's speed just before impact.

Kinematics: Speed and distance problem.

A car is initially 3.0 km south of a gas station and is moving with a constant speed of 50 km/h due north. A truck is initially 5.0 km north of the gas station and is moving with a constant speed of 40 km/h due south. How far are the vehicles from the gas station when they pass each other?

Work done by a varying force.

An object is under the force F = (k1*x) i - (k2*y) j. Calculate the work done by this force when the object: a) moves on the x-axis from the origin to the point (a,0), and then goes from (a,0) until (a,b) parallel to the y-axis; b) moves from the origin to the point (0,b), and then goes from (0,b) until (a,b) parallel to t

Force and Flooding Problems

The story goes that a boy in Holland saved his country from being flooded by plugging a hole in the sea wall with his finger. Parts of Holland are lower than sea level and walls have been built to keep the sea out. If the hole was 2.00m below sea level and the density of the North Sea is 1030 kg/m3. a) What was the force on h

Rate of Heat Removal Problem

A Carnot refrigerator operates in a room in which the temperature is 25oC. The refrigerator consumes 500W of power when operating and has a coefficient of performance ?=4.5. Determine the rate of heat removal from the refrigerated space and the temperature of the refrigerated space.

Classical Mechanics Problem

Please show all the work. The pump shown in the figure (please see the attachment for it) creates a flow such that V = 15 m/s. Predict the pressure at the gage assuming an inviscid and uniform flow at the gage. Use a streamline starting at : a. Point A b. Point B

Horizontal work on an object

Matthew pulls his little sister Sarah in a sled on an icy surface (assuming no friction), with a force of 60.0 N at an angle of 37.0 degrees above the horizontal. If he pulls her a distance of 12.0 m, what is the work done by Matthew?

Solving a Physics Problem

A car is going around a flat curve of radius 50 m at a speed of 20 m/s. The centripetal force provided by friction is 12,000 N. What is the mass of the car? Please provide detailed explanation and reflect your work with units.

Problem with Centripetal Acceleration

What is the centripetal acceleration of a point on the perimeter of a bicycle wheel of diameter 70 cm when the bike is moving 8.0 m/s? [Hint: The speed of the bike is also the speed of a point on the perimeter of the wheel.] Please provide detailed explanation and reflect your work with units.

Work done in compressing a fluid

A pump is used to raise the pressure of diesel fuel. It is measured that power needed to drive this pump is 5 kW for the steady operation (dE/dt = 0 for the system) (m in = m out). The efficiency of this perfect pump is 100% (all the energy is used to raise the pressure of diesel fuel). The density of diesel fuel is 800

Finding the frequency of wavelength

I have attached a problem asking me to prove that a wavelength has a certain frequency. I am a little confused on how to approach the problem. I would appreciate an explanation and work. Thank you for the assistance.

Negative Charge and New Positions

1) A negative charge of q = -1 C moves from position <0.2, -0.3, -0.7> m to a new position <0.1, -0.3, -0.4>m. in these region there is an electric field of E = <2000, 2000> N/C. how much work is done on the charge by the electric force? a) 9000J b) 1500J c) 200J d) NA 2) An electric filed of E = <500, 0, 0> N/C is est

Work Done by the Gas on the Bullet

A 136 g bullet is fired from a rifle having a barrel 0.935 m long. Assuming the origin is placed where the bullet begins to move, the force exerted on the bullet by the expanding gas is F = a + bx - cx^2, where a = 20600 N, b = 5680 N/m, c = 39900 N/m^2, with x in meters. Determine the work done by the gas on the bullet as th

the work done against friction

Starting from rest at a height equal to the radius of the circular track, a block of mass 30 kg slides down a quarter circular track under the influence of gravity with friction present (of coefficient mu). The radius of the track is 35 m. The acceleration of gravity is 9.8 m/s^2. If the kinetic energy of the block at the bo

Physics: Electric Field Problem

A uniform electric field of strength 56000 N/C exists between the plates of a capacitor. The plates are 2 cm apart. How much work is required to move a charge of 1 * 10^-3 Coulombs from one plate to the other?

Work, Friction and Height

A 10.0 kg block slides down a plane inclined at an angle of 53 degrees to the horizontal from an initial height of 40.0 m the coefficient of kinetic friction between the block and the inclined plane is 0.300. The block continues to slide 20.0 m across a horizontal surface. The coefficient of kinetic friction between the block a