Thursday

August 28, 2014

August 28, 2014

Number of results: 86,115

**science**

What is the difference in Thermal Energy and Heat.
*October 24, 2011 by Anna*

**Science**

What is the source of energy in fossil fuels?
*November 2, 2011 by Bob*

**Science**

What are they asking in this question? Which is an alternative source of energy?
*November 8, 2011 by Bob*

**physics**

the differences between work and energy??
*November 27, 2011 by west*

**chemistry **

what is the energy in joules of one quantum of 55.4 nm
*February 4, 2012 by Anonymous*

**SCIENCE**

FOOD & HEALTH SOURCE & ENERGY
*May 25, 2012 by SS*

**PHSC**

Which part of a wave relates to its energy ?
*July 5, 2012 by brandy*

**physics**

Which part of a wave relates to its energy ?
*July 5, 2012 by brandy*

**chemistry**

What is the wavelength of a photon that has an energy of E = 4.01×10^-19J ?
*July 7, 2012 by Larry*

**science**

heat energy is measured in unites of
*August 25, 2012 by diane*

**Science **

What's a benefit and risk of nuclear energy?
*January 16, 2013 by Cassidy*

**chemistry**

Calculate the wavelength of a photon with energy 2.45 eV.
*February 25, 2013 by adex*

**chemistry**

Calculate the wavelength of a proton with energy 2.45 eV.
*February 25, 2013 by adex*

**science**

what are the changes of statein which energy is increased
*April 28, 2013 by jj*

**social studies**

What is the responsibility's of the department of energy
*May 28, 2013 by Hannah*

**Chemistry**

Calculate the wavelength of a proton with energy 2.45 eV.
*September 15, 2013 by Anon*

**physics**

what are imp. l/q of unit 6 (work and energy)
*September 24, 2013 by hamza*

**Science**

What equipment is necessary for wind energy?
*January 9, 2014 by Anonymous*

**physics**

what forms of energy does pendulm have/
*February 16, 2014 by uk girl*

**Desperate need of Help for Physics.**

Moment of inertia of a flywheel disk question: Do you think the calculated moment of inertia is larger or smaller than the "true" moment of inertial of the actual disk? question: calculate the percent difference between the static and the dynamic moment. I got .0195kgm^2 for ...
*November 15, 2006 by Teesha*

**math**

PLEASE!!!!i need help on these 4: *4y=15-3x 2y=3x+21 *4x=5y-14 y=-6x-9 *5x=4y-30 2x=3y=-12 *2/3y=10+4x 5x=1/3y-8 use linear combinations to solve the system of linear equations thank you!!!
*January 24, 2011 by HELP me please asap!!*

**math**

PLEASE!!!!i need help on these 4: *4y=15-3x 2y=3x+21 *4x=5y-14 y=-6x-9 *5x=4y-30 2x=3y=-12 *2/3y=10+4x 5x=1/3y-8 use linear combinations to solve the system of linear equations thank you!!!
*January 24, 2011 by HELP me please asap!!*

**linear equation**

For the following linear inequalities draw the feasibile region i: x _>1 ii: x+y _<2 iii: x-axis
*February 27, 2011 by winning*

**physics**

An object of mass M = 4 kg slides from rest a distance d = 2 m down a frictionless inclined plane where it encounters a spring. It compresses the spring a distance D = 1.2 m before stopping. The inclined plane makes an angle q = 20° with the horizontal. a) When the block just ...
*March 11, 2012 by Mel*

**Physics**

Suppose the skin temperature of a naked person is 34°C when the person is standing inside a room whose temperature is 25°C. The skin area of the individual is 2.0 m2 a) Assuming the emissivity is 0.80, find the net loss of radiant power from the body b) Determine the number of...
*April 18, 2007 by papito Urgent help needed*

**Science**

5. Which of the following types of pollution cannot be attributed to car and truck emissions? A. acid rain B. sedimentation C. ozone D. photochemical smog 6. Which of the following is a source of photochemical smog? A. fossil fuels B. wind energy C. biomass fuels D. nuclear ...
*March 20, 2014 by Anonymous*

**Math**

What similarities and differences do you see between functions and linear equations studied in Ch. 3? Are all linear equations functions? Is there an instance in which a linear equation is not a function? Support your answer. Create an equation of a nonlinear function and ...
*September 28, 2009 by Toni*

**math**

What similarities and differences do you see between functions and linear equations studied in Ch. 3? Are all linear equations functions? Is there an instance in which a linear equation is not a function? Support your answer. Create an equation of a nonlinear function and ...
*October 27, 2009 by tye*

**math**

What similarities and differences do you see between functions and linear equations studied in Ch. 3? Are all linear equations functions? Is there an instance when a linear equation is not a function? Support your answer. Create an equation of a nonlinear function and provide ...
*October 5, 2010 by afrika*

**Physics**

A ball is falling through the air. It has just two forces acting on it, its weight and air resistance. Which of the following statements is true? a. There are only conservative forces acting on the ball. b. There are only nonconservative forces acting on the ball. c. There are...
*December 12, 2011 by Sarah*

**physics**

two crates, of mass 75 kg and 113 kg, are in contact and at rest on a horizontal surface. A 727 N force is exerted on the 75 kg crate. If the coefficient of kinetic friction is 0.15, calculate the following: a)the acceleration of the system b) the force that each crate exerts ...
*November 22, 2010 by Haley*

**physics**

Two boxes of fruit on a frictionless horizontal surface are connected by a light string as in the figures below, where m1 = 10 kg and m2 = 19 kg. A force of 46 N is applied to the 19 kg box. Repeat the problem for the case where the coefficient of kinetic friction between each...
*October 4, 2012 by Anonymous*

**chemistry**

Use the kinetic molecular theory of gases to explain each of the following: a. a container of nonstick cooking spray explodes when thrown into a fire. b. the air in a hot-air balloon is heated to make the balloon rise.
*November 10, 2012 by Boo Boo*

**physics**

a truck of mass 8500Kg is pulling a trailer of mass 27 000Kg on a level road.The coefficient of kinetic friction is 0,20.A horizontal force of 75 000N moves the truck forward.question:calculate the magnitude of the acceleration of the system
*March 3, 2014 by Bheki*

**physics**

The three objects in the drawing are connected by strings that pass over massless and friction-free pulleys. The objects move, and the coefficient of kinetic friction between the middle object and the surface of the table is 0.100. (Assume m1 = 12.2 kg and m2 = 26.0 kg.)
*May 27, 2014 by twill*

**physics**

A revolutionary new diet advertises that one can lose weight simply by eating ice. When one eats ice,chemical energy in the body is used to melt the ice and then raise the temperature of the melted ice to the temperature of the body, 37 degrees Celsius.Past scientific studies ...
*January 22, 2011 by jenny*

**graphics**

other than speed of production, what are two advantages of CAG (computer aided graphics) over manual methods? Thank you for using the Jiskha Homework Help Forum. Because it is faster, it is more energy conscious and leads to more profitability. In addition, computer graphics ...
*March 13, 2007 by chelsea*

**physics**

A 4.8 kg block is pushed along the ceiling with a constant applied force of 87 N that acts at an angle of 55.0° with the horizontal, as in Figure 4-33. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between the block and the ...
*December 5, 2010 by Corey*

**physics**

What is the minimum downward force on the box ( m=30 kg)that will keep it from slipping? The coefficients of static and kinetic friction between the box and the floor are 0.40 and 0.30, respectively.One person is pulling the box forward with a force of 125 N.
*December 7, 2010 by vinu*

**physics**

a 160g hockey puck slides horizontally along the ice, and the coefficient of kinetic friction between puck and ice is 0.15. if the puck starts sliding at 3 m/s before it comes to a stop it travels 3.6m how do you get to this answer?
*October 28, 2011 by annie*

**Physics**

A 4.4 kg block is pushed along the ceiling with a constant applied force of 89 N that acts at an angle of 55.0° with the horizontal, as in Figure 4-33. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of kinetic friction between the block and the ...
*December 2, 2011 by Kashawn*

**physics**

Object A has a gravitational potential energy of 24 joules when it rests on a shelf 5 m above the ground. Object B has a mass that is three times the mass of Object A. What would be the gravitational potential energy of object B when it rests on a shelf 10 m above the ground...
*October 22, 2009 by roxy*

**mechanics**

A wad of sticky clay of massmand velocity vi is fired at a solid cylinder of massM and radius R. The cylinder is initially at rest and is mounted on a fixed horizontal axle that runs through the center of mass. The line of motion of the projectile is perpendicular to the axle ...
*December 9, 2010 by sana*

**physics**

If an airplane propeller rotates at 1570 rev/min while the airplane flies at a speed of 333 km/h relative to the ground, what is the linear speed of a point on the tip of the propeller, at radius 1.97 m, as seen by (a) the pilot and (b) an observer on the ground? The plane's ...
*November 9, 2011 by kyle*

**Physics HELP!**

A war-wolf, or trebuchet, is a device used during the Middle Ages to throw rocks at castles and now sometimes used to fling pumpkins and pianos. A simple trebuchet is shown in the figure. Model it as a stiff rod of negligible mass 3.00 m long and joining particles of mass 74....
*November 6, 2012 by Holly*

**Math 116**

What similarities and differances do you see between functions and linear equations studied in Ch.3? are all linear equations functions? is there an instance when a linear equation is not a function? support your answer. create an equation of a nonlinear function and provide ...
*July 18, 2008 by Sam*

**physics**

A 1.8 kg object is pulled along the floor with a force of 7.0 N acting horizontally. If the object accelerates at 2.4m/s^2, how much kinetic friction is acting? how do i do this? could you please explain step by step
*December 3, 2009 by kerri*

**physics**

The coefficient of kinetic friction between a refrigerator (mass 93 kg) and the floor is 0.12, and the coefficient of static friction is 0.35. If you apply the minimum force needed to get the refrigerator to move, what will the acceleration then be?
*September 29, 2010 by jerr *******

**Physics**

A pure copper penny is slid along a steel counter top. If the coefficient of kinetic friction between the copper and the steel is 0.36, what is the magnitude of the penny's acceleration?
*October 19, 2011 by Sammy*

**physics**

A 1.5-kg cart is pulled with a force of 7.3 N at an angle of 40° above the horizontal. If a kinetic friction force of 3.2 N acts against the motion, the cart’s acceleration along the horizontal surface will be
*November 12, 2011 by joe*

**physics**

A box slides down a 33.3 ◦ ramp with an acceleration of 1.07 m/s 2 . The acceleration of gravity is 9.8 m/s 2 . Determine the coeﬃcient of kinetic friction between the box and the ramp.
*December 6, 2012 by Anonymous*

**PHYSICS**

A 7 kilogram bowling ball is dropped from a fourth story window. If each story is 3 meters high, use energy conservation (not the equations of motion) to find the ball's velocity when it strikes the ground. Ignore air resistance. Thank you
*February 23, 2012 by GRISSELL*

**PHYSICS**

A 7 kilogram bowling ball is dropped from a fourth story window. If each story is 3 meters high, use energy conservation (not the equations of motion) to find the ball's velocity when it strikes the ground. Ignore air resistance.
*February 26, 2012 by TRACY*

**Physics**

A weight lifter manages to lift a 147 kg weight a distance of 1.1 m. Treat her as a thermodynamic system and find how much heat (in kcal) she must put out if her internal energy decreases by 3620 J during the lift.
*January 31, 2014 by Riley *

**Algebra HELP**

USE LINEAR COMBINATIONS TO SOLVE THE SYSTEM OF LINEAR EQUATIONS (please show steps) 1) -X+8Y=16 2) 4X+5Y=-2 3)4Y=15-3X 3X+4Y=36 5X-4Y=-23 2Y=3X+21
*December 13, 2007 by electra*

**Math**

What are some key words when choosing whether to use a linear equation or a linear inequality?
*August 24, 2009 by Terilee*

**algebra**

what similarities and differences are there between functions and linear equations? Is there an instance when a linear equation is not a function?
*April 12, 2010 by nala*

**maths**

use the substitution method to solve the linear system. 1. 3x=9 -x+2y=9 3x/3 = 9/3 x = 3 -x(3)+2y = 9 -3+2y = 9 2y = 12 y = 6 is (3,6) correct? =========== also, can you please tell me how to solve these? use the linear combinations to solve the linear system: 2.x+y=3 x+2y=6 3...
*November 17, 2009 by jenn*

**Algebra**

linear equations is it a linear equation? 3x=5y i got yes since 0=5y-3x
*October 2, 2008 by Alejandro*

**linear equations**

What is the solution to the linear system –4x + 2y = –56 and –3x – 6y = 33?Question 3 options: (–9, 10) (–9, –10) (9, 10) (9, –10)
*January 5, 2011 by alli*

**Math**

Express the non linear equation in its linear form; y=nx^(1/2)+kx
*February 17, 2013 by azmeerahim*

**CONSERVING HOME ENERGY**

READ EACH OF THE STATEMENTS BELOW. THEN, IN ONE OR TWO WORDS, WRITE WHAT YOU COULD DO TO CONSERVE ENERGY FOR THAT PARTICULAR ITEM. 1. A DRIPPING FAUCET 2. AN OPEN WINDOW WITH HEAT ON 3. DRAFT AROUND A CLOSED DOOR 4. THROWING OUT PLASTIC CONTAINERS 5. LIGHTS LEFT ON 6. ...
*September 20, 2006 by PEACHES*

**Chemistry**

Glycine,C2H502N, is important for biological energy.Find the heat of combustion deltaHrxn. Delta H [C2H5O2N]=-537.3 kj/mol DeltaH [ CO2(g)=-393.5 kj/mol DeltaH[H2O(l)]-285.8 kj/mol
*November 15, 2011 by Nicole*

**physics**

Suppose a sound of frequency 1200 Hz is emitted from a speaker 15 meters away from you. At YOUR location, the intensity is 1.0E-7 W/m2. Let me assume your eardrum has area 8E-5 m2. If the sound continues for 20 seconds, what total amount of energy is received by your ear? Find...
*March 3, 2011 by Student in Need*

**physics**

Suppose a sound of frequency 1200 Hz is emitted from a speaker 15 meters away from you. At YOUR location, the intensity is 1.0E-7 W/m2. Let me assume your eardrum has area 8E-5 m2. If the sound continues for 20 seconds, what total amount of energy is received by your ear? Find...
*March 4, 2011 by student in need*

**Physics**

A bullet of mass 45 g is fired at a speed of 220 m/s into a 5.0-kg sandbag hanging from a string from the ceiling. The sandbag absorbs the bullet and begins to swing. To what maximum vertical height will it rise? Hint: Energy is not conserved as the bullet enters the bag but ...
*February 3, 2013 by Khalifa *

**physics**

A satellite moves in a circular orbit around Earth at a speed of 4390 m/s. (a) Determine the satellite's altitude above the surface of Earth. m (b) Determine the period of the satellite's orbit. h am I supposed to use rotational equations for this? I don't know what to start ...
*April 7, 2010 by Kelsey*

**Pchem**

2 NO2(g) N2(g) + 2 O2(g) The ¥ÄH¡Æ for the reaction above is -66.4 kJ. The system is initially at equilibrium. What happens if NO2 is added to the reaction mixture at constant temperature and volume? (Select all that apply.) And here's the options. The reaction absorbs energy...
*February 17, 2010 by JCY*

**physics**

-Using a digital camera, you are taking a picture of your 1.80meter-tall friend standing at a distance of one meter from you. From the camera manual, you learned that the size of the sensor (electronic film) is 6mmx8mm. In other words, the sensor is rectangular with 6mm on one...
*February 22, 2009 by JeFF*

**chemistry**

2 NO2(g) N2(g) + 2 O2(g) The ΔH° for the reaction above is -66.4 kJ. The system is initially at equilibrium. What happens if N2 is added to the reaction mixture at constant temperature and volume? The reaction absorbs energy. The reaction releases energy. [NO2] increases...
*September 19, 2010 by Megan*

**physics**

The coefficient of kinetic friction between a refrigerator (mass 93 kg) and the floor is 0.12, and the coefficient of static friction is 0.35. If you apply the minimum force needed to get the refrigerator to move, what will the acceleration then be? ____ m/s2
*September 29, 2010 by Anonymous*

**physics**

What force must be applied to push a carton weighing 220 N up a 20° incline, if the coefficient of kinetic friction is 0.39? Assume the force is applied parallel to the incline and the velocity is constant
*November 14, 2011 by Sam*

**science**

2. How do enzymes impact biochemical reactions in the body? A. Enzymes are catalysts to biochemical reactions. B. Enzymes lower the activation energy of biochemical reactions. C. Enzymes can speed up biochemical reactions. D. All of the above are correct.
*November 6, 2013 by hannah *

**physics**

A turntable must spin at 33.7 rpm (3.53 rad/s) to play an old-fashioned vinyl record. How much torque must the motor deliver if the turntable is to reach its final angular speed in 1.5 revolutions, starting from rest? The turntable is a uniform disk of diameter 30.5 cm and ...
*March 17, 2012 by Keith*

**Chemistry**

Find the amount of energy absorbed by 10.0 g of water when the temperature is increased from 10.0 degrees celcius to 20.0 degrees celcius? What is this amount in calories? KCAL?
*April 10, 2014 by Mak*

**physics**

A spring and mass system are oscillating with an amplitude of 8.4 cm. The spring constant is 204 N/m and the mass is 540 g. Find the mechanical energy of the system to 2 sf.
*June 15, 2014 by jake*

**Physics**

A 10kg particle undergoes simple harmonic motion with an amplitude of 2.0mm, a maximum acceleration of 8.0x10^3 m/s^2, and an unknown phase constant (phi) What are: a.) the period of the motion b.) the maximum speed of the particle c.) total mechanical energy of the oscillator...
*November 30, 2010 by Greg*

**physics**

A baseball pitcher throws a baseball horizontally at a linear speed of 41.3 m/s. Before being caught, the baseball travels a horizontal distance of 15.4 m and rotates through an angle of 52.7 rad. The baseball has a radius of 3.74 cm and is rotating about an axis as it travels...
*April 9, 2014 by Anonymous*

**calculus**

Find the volume V of the described solid S. The base of S is a circular disk with radius 2r. Parallel cross-sections perpendicular to the base are squares.
*November 10, 2011 by Johnathon*

**Math**

Find the volume V of the described solid S. The base of S is a circular disk with radius 4r. Parallel cross-sections perpendicular to the base are squares.
*January 21, 2013 by Em*

**math, calc 2**

Using the disk method, find the volume of a right circular cone with height h and base radius r. I know the answer is 1/3pier^2h, but how do you explain or work out the problem?
*January 17, 2007 by George*

**Helpppp Math!!!**

The market value (in thousands of dollars)of a certain home is a linear function of t, the time in years since 1990. In 1992 the market value was 68 thousand dollars, while in 1997 the market value was 79 thousand dollars -Find the slope of V as a linear function of t. Explain...
*April 29, 2014 by Kim*

**Physics**

Consider a single photon with a wavelength of λ, a frequency of ν, and an energy of E. What is the wavelength, frequency, and energy of a pulse of light containing 100 of these photons? A)100λ, 100ν, and E B)0.01λ, ν, and 100E C)λ, ν, ...
*April 20, 2013 by Shai*

**Physics**

A box is being with a velocity v by a force P (parallel to to v) along a level horizontal floor. the normal force is Fn, the kinetic frictional force if fk, and the weight of the box is mg. Decide which forces do positive, zero or negative work and why?
*February 12, 2012 by Nilan*

**Physics**

A box is being moved with a velocity (v) by a force (p)(parallel to v) along a level horizontal floor. The normal force is (Fn), the kinetic frictional force is (fk), and the weight of the is box is (mg). Draw a free-body diagram of this situation
*February 13, 2012 by Amy*

**Physics(Please help)**

A skier slides horizontally along the snow for a distance of 11.9 m before coming to rest. The coefficient of kinetic friction between the skier and the snow is 0.0458. Initially, how fast was the skier going? I do not know how to start this. Thank you.
*June 1, 2012 by Hannah*

**physics**

A 3.40 kg block is pushed along the ceiling with an constant applied force of F = 82.0 N that acts at an angle θ = 50° with the horizontal. The block accelerates to the right at 5.80 m/s2. Determine the coefficient of kinetic friction between the block and the ceiling. &#...
*January 13, 2013 by Elli Johnson*

**physics**

the spring that has spring constant of 100N/M. It is compressed 15cm,then launches a200g block. The horizontal surface is frictionless, but the block has coefficient of kinetic friction on the incline is 0.20. What distance block sail through the air?
*October 18, 2013 by simiso*

**SCIENCE,PHYSICS**

A thin ring with resistance R=10 Ω and self inductance L=0.2 H rotates with constant angular speed ω=100 rad/s in an external uniform magnetic field perpendicular to the rotation axis. As a result, the magnetic flux created by the external field varies with time as...
*July 18, 2013 by kk*

**physics**

A 100 kg mass starts from rest at the top of an incline plane that makes an angle of 35 degrees with the horizontal. There is a coefficient of friction of 0.005 between the ramp and the mass. The mass slides down the ramp and then slides to a stop on a surface that the ...
*May 14, 2010 by Steven*

**science grade 5**

how is heat related to temperature? Temperature tells us the DEGREE of heat; i.e., how hot is something. A temperature of 98.6 F is normal body temperature. A hot day is when the temperature is 95 degrees F. A cold day is when it is freezing outside. But the heat something ...
*November 15, 2006 by kathy*

**chemistry**

Use the kinetic theory of gases to explain this statement: No gas exhibits ideal behavior at all temperatures and pressures. Explain why the rates of diffusion of nitrogen gas and carbon monoxide are almost identical at the same temperature.
*March 4, 2008 by jodi*

**Pls help me now**

A 75g person on skis is going down a hill sloped at an angle 30.the coefficient of kinetic friction between the skis and the snow is 0.15.how fast is the skier going 10s after starting from rest?(answer=36m/s)
*November 6, 2011 by Henneh *

**physics**

an experimental rocket plane lands on skids on a dry lake bed. it is traveling at 80.0 m/s when it touches down, how far does it slide before it comes to a stop? assume the coeffcient of kinetic friction between the skids and the lake is .600
*March 5, 2012 by sarah*

**Physics**

A 0.400 kg block of wood hangs from the ceiling by a string, and a 0.0700 kg wad of putty is thrown straight upward, striking the bottom of the block with a speed of 5.80 m/s. The wad of putty sticks to the block. Is the mechanical energy of this system conserved? yes or no (b...
*November 14, 2010 by Josie*

**Math**

Show that the transformation T:R^2->R^2 given T(x1,x2)=(3x1-5x2,x1+2x2) is linear by verifying that satisfies the defination of linear.
*August 13, 2010 by Jason*

**math**

i only need help on these two: *2/3y=10+4x 5x=1/3y-8 *5x=4y-30 2x+3y=-12 DIRECTIONS:use linear combinations to solve the system of linear equations.. thanks :)
*January 24, 2011 by HELP me please *

**Physics**

A person pushes horizontally with a force of 270 N on a 55 kg crate to move it across a level floor. The coefficient of kinetic friction is 0.25. What is the magnitude of the frictional force? What is the magnitude of the crate's acceleration?
*October 21, 2010 by Sam*

**physics**

A 280 N force is pulling an 80.0 kg refrigerator across a horizontal surface. The force acts at an angle of 18.0° above the surface. The coefficient of kinetic friction is 0.200, and the refrigerator moves a distance of 8.00 m.
*October 28, 2010 by Anonymous*

**physics**

A person pushes horizontally with a force of 170 N on a 68 kg crate to move it across a level floor. The coefficient of kinetic friction is 0.22. (a) What is the magnitude of the frictional force? (b) What is the magnitude of the crate's acceleration?
*October 11, 2011 by Andrew*

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