Explore BrainMass

# Work

## BrainMass Solutions Available for Instant Download

### Six problems on mechanics.

(Please see the attachment for questions, complete with diagrams/figures) 2. If the 10-kg ball has a velocity of 3 m/s when it is at the position A, along the vertical path, determine the tension in the cord at this position and the magnitude of acceleration of the ball at this position. 3. The 2-Mg car is being towed by

### Work Required to Stretch a Spring; Elastic Potential Energy

Explain why the work required to stretch a spring or other elastic object with a linear restoring force, of form F = - kx, from its equilibrium position to displacement x is `dW = .5 k x^2, and why we hence say that this is the elastic potential energy of the object in this position.

### Work, Energy, Velocity & Power: Example Questions

Problem 1: The dumbwaiter D and its load have a combined mass of 300kg, while the counterweight C has a mass of 400 kg. Determine the power delivered by the electric motor M when the dumbwaiter: (a) is moving up at a constant speed of 2.5 m/s; (b) has an instantaneous velocity of 2.5 m/s and an acceleration of 0.75 m/s^2,

### Current Needed to Generate the Magnetic Field Strength

Could you please show work for only the first question and simply provide me with the answer to the remaining question so I actually get a chance to practice and check. 1. What current is needed to generate the magnetic field strength of 5.0 x 10^-5 T at a point 1.7 cm from a long, straight wire? I=________A 2. What c

### Energy needed to raise the temperature of a balloon of helium

A balloon contains 10 liters of helium gas at 17 degrees C and 0.99 atm. How much energy must be added to raise the temperature of the helium to 37 degrees C while allowing the balloon to expand and stay at the same pressure.

### Kinetic Energy, Point Charges, Electric Field and Potential

A charged particle with a charge of +5.0 micro coulombs is initially at rest. It is accelerated through a potential difference of 500 V. What is the kinetic energy of this charged particle? Two point charges of magnitude +4.00 MicroC and +2.00 microC are placed at opposite corners (top right, lower left) of a rectangle 0.800m

### Dynamics of a two car collision

A dynamics student is called on to investigate a two car collision. It is known that car A sruck car B (see attahment). mA = 2000 kg and mB = 1200 kg. Both cars A and B then skidded 8.0 m. It apears from the damage that car A struck car B at a relative speed of 12 m/s. Find the speed of car A just before collision. Assume a

### Acceleration (Work) Done by Aircraft When It Launches

An aircraft weighing 941 N is accelerated at 8 m/s/s for 14 seconds, at which time the aircraft launches. How much work was done on the aircraft? The acceleration is constant. Hint: This is a multiple step problem in which you must derive the variables needed (mass and distance under constant acceleration) in step one and th

### Kinetic energy of gas: Thermal energy and speed of molecules

The rms speed of the molecules in 1.9 g of hydrogen gas is 1800 m/s . a) What is the total translational kinetic energy of the gas molecules? b) What is the thermal energy of the gas? c) 500 J of work are done to compress the gas while, in the same process, 1400 J of heat energy are transferred from the gas to the env

### Guitar String Frequency and Vibrations

1. What happens to the guitar strings during tuning that changes the frequency of the vibrations? Explain how it works. 2. When playing a guitar, which physical parameter of a guitar string must the player change to get various tones from the same string?

### Maximum Kinetic Energy Attained by a Body

The only force acting on a 2.0Kg body as it moves along the x axis is given by FX =(12-2.0X)N where x is in m. the velocity of the body at x= 2.0m is 5.5i m/s. What is the maximun kinetic energy attained by the body?

### Physics: Coefficient of friction, Coefficient of kinetic friction

1. A 400lb body is pulled up an inclined plane 15 ft long and 5 ft high. The force to pull the body up the plan at constant speed is 200lb. Compute ideal mechanical advantage (IMA = 15/5 =3) actual mechanical advantage (AMA = P/F = (400/2.2 x 9.8)/200/2.2 x9.8) = 2). What is the coefficient of friction between the body and the p

### Busterina be able to catch the ball thrown in the air by Buster

Buster does 300J of work on the ball to throw it into the air. It goes straight up and back down. Busterina Leaves at the same time from 10M away at a constant velocity of 2m/s. Will she be able to catch the ball before it hits the around? The ball mass is 2 kg.

### Work and Energy Problems

Questions: Work and Energy Review Problems (Answers are at the bottom of this document) 1. From the given list, select a possible pair for the value of coefficient of static and kinetic frictions &#956;s and &#956;k (There may be more than one choice) a. (2.61, 2.00) b. (2.00, 2.61) c. (0.261, 0.150)

### Thermal Expansion: Cold Welding

2) An apparatus consisting of a rod (made of material A) placed inside a tube (made of material B) must be fabricated so that the rod fits tightly into the tube at room temperature. One way to do this is through the process of cold welding in which both pieces are cooled in liquid nitrogen and the rod then fits loosely into the

### Using point charges to determine potential at a given point

3 point charges Q1, Q2, Q3 are located in the xy plane at points (-10,0), (10,0) and (-5,12) respectively. The charges are given values Q1 = 5 uC, Q2 = -10 uC, Q3 = 8 uC. You may assume that the distance between charges is in units of cm (A) Calculate the Electric Potential at the origin, point (0,0) (B) Determine the

### Work, Energy & Power Physics

The motor of a ski boat generates an average power of 6.90 x 10^4 W when the boat is moving at a constant speed of 15 m/s. When the boat is pulling a skier at the same speed, the engine must generate an average power of 8.70 x10^4 W. What is the tension in the tow rope that is pulling the skier? The drawing shows the force-v

### bullet hitting a wooden block

A bullet with a mass of 3.00 g, traveling horizontally with a speed of 420 m/s, is fired into a wooden block with mass of 0.840 kg , initially at rest on a level surface. The bullet passes through the block and emerges with its speed reduced to 180m/s . The block slides a distance of 48.0 cm along the surface from its initial po

### Electrostatic potential energy & electrical potential

See attached file. The problems are from Physics 7th edition by Cutnell & Johnson. 1. During a particular thunderstorm, the electric potential difference between a cloud and the ground is Vcloud - Vground = 1.90 108 V, with the cloud being at the higher potential. What is the change in an electron's electric potential ene

### Speed and distance of a rock as it leaves a cliff

See attached file. A 61 kg boulder is rolling horizontally at the top of a vertical cliff that is 20 m above the surface of a lake, as shown in the figure. The top of the vertical face of a dam is located 100 m from the foot of the cliff, with the top of the dam level with the surface of the water in the lake. A level plain i

### Free-Body Diagram, Tension and Reaction Forces

Please show your work as I need to understand the solution well. A uniform vertical beam of mass 35 kg is acted on by a horizontal force of 520 N at its top and is held, in the vertical position, by a cable as shown in the attachment. a. Draw a free-body diagram for the beam, clearly labeling all of the forces acting on it

### Work done by pressure forcing water through a pipe

Problem 61 How much work is done by pressure in forcing 9.6 m3 of water through a pipe having an internal diameter of 13 mm if the difference in pressure at the two ends of the pipe is 3.2 atm? Problem 81 Tin can has a total volume of 1380 cm3 and a mass of 146 g. How many grams of lead shot of density 11.4 g/cm3 could

### Seven Physics Problems

Please show work. 1. Consider the energy of a 100 kg rock. a) What is the gravitational potential energy (PE) of the rock that is on a table 5 m above the ground? b) The rock falls to the ground. What is its PE on the ground? c) What is the change in PE of the rock from the table to the ground? d) From conservation of e

### Kinetic Energy of a Charged Particle

Part 1 An electron starting from rest acquires 3.19 keV of kinetic energy in moving from point A to point B. How much kinetic energy would a proton acquire, starting from rest at B and moving to point A? Part II Determine the ratio of their speeds at the end of their respective trajectories. -PLEASE EXPLAIN PROBLEM

### Proton Potential Point

How much work is needed to move a proton from a point with a potential of +410 V to a point where it is -30.0 V? Express your answer in joules. Express your answer in electron volts. Please a provide a detailed explanation.

### Force and Motion

019 (part 1 of 4) A 39.1 kg box initially at rest is pushed 3.94 m along a rough, horizontal floor with a constant applied horizontal force of 67.462 N. If the coefficient of friction between box and floor is 0.139, find the work done by the applied force. The acceleration of gravity is 9.8 m/s2 . Answer in units of J. 020

### F, m, wt are found. Work done by difference forces is found.

1. In a college homecoming competition, eighteen students lift a sports car. While holding the car off the ground, each students exerts an upward force of 400 N. (a) What is the mass of the car in kilograms? (b) What is its weight in pounds? 2. A block on a level frictionless surface has two horizontal forces applied. (a) Wha

### General Physics: Work and Newton's Third Law

1. Nancy claims that she does more work in lifting her toddler each day than Atlas ever did when holding the whole world on his shoulders. is she correct? 2. Given Newton's third law of motion, why is there no "equal and opposite reaction" when you jump into the air?

### Coupled Oscillator - Quantum Mechanics

Please help solving the attached problem. Please note that part 4(c) is cut off and is continued on the next file. Please only solve if you are 100% certain your work is correct. Please show all work needed to arrive at the solution.

### Newtons law application-example

In the 1950s, an experimental train that had a mass of 2.10 x10^4 kg was powered across a level track by a jet engine that produced a thrust of 5.45 x 10^5 N for a distance of 509 m. Assume that air resistance is negligible. (a) Find the work done on the train. J (b) Find the change in kinetic energy. J (c) Find the