Thursday
December 18, 2014

Search: "A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. "

Number of results: 51,080

physics
Two blocks, each with a mass m = 0.400 kg, can slide without friction on a horizontal surface. Initially, block 1 is in motion with a speed $v$ = 1.20 m/s; block 2 is at rest. When block 1 collides with block 2, a spring bumper on block 1 is compressed. Maximum compression of ...
March 5, 2014 by Ted

physics (simple question...need help pls!)
The magnetic field is generated by: A) an electron moving at constant speed in a straight line B) a proton moving in a circle C)a neutron moving in a circle D) none
June 7, 2011 by john

physics
A proton that has a mass m and is moving at 250 m/s in the + direction undergoes a head-on elastic collision with a stationary oxygen nucleus of mass 16m. Find the velocities of the proton and the carbon nucleus after the collision
May 6, 2012 by help please

Physics
Thanks for taking a look! A baseball of mass m1 = 0.46 kg is thrown at a concrete block m2 = 8.25 kg. The block has a coefficient of static friction of μs = 0.81 between it and the floor. The ball is in contact with the block for t = 0.165 s while it collides elastically...
March 25, 2014 by Michelle

physics
In the Atwood's machine of Figure 8-23, the two masses shown are initially at rest at the same height. After they are released, the large mass, m2, falls through a height h and hits the floor, and the small mass, m1, rises through a height h. The mass m2 remains at rest once ...
March 31, 2011 by jennifer

physics
What gravitational force do the two protons in the helium nucleus exert on each other? Their separation is approximately 1.0 {\rm fm}.
November 4, 2010 by jack

Physics
In 1910 Rutherford performed a classic experiment in which he directed a beam of alpha particles at a thin gold foil. He unexpectedly observed a few of the particles scattered almost directly backward. This result was not consistent with then current models of atomic ...
July 2, 2014 by Brandi

POP
2. A truck moves with a certain momentum. If both its speed and its mass are doubled, how much greater is its momentum? A) Two times. B) Four times. C) Eight times. D) Unchanged, the same.
February 19, 2012 by Anonymous

college
A spaceship lands on the planet whose radius is 5 times that of planet earth and whose mass is 25 times that of planet earth. Find the apparent weight of the astronaut on the second planet if the astronaut weighs 150lbs on planet earth
November 1, 2010 by Antonio

chem
A carbon nucleus has six protons and six neutrons. How many electrons would it take to equal the mass of a carbon nucleus? my teacher said 6pt x conversion to make kg and then add that to 6nx conversion to make kilograms. then that times conversion for electrons. so kg x 1e-/....
September 21, 2010 by Sara

principles of physics
A truck moves with a certain momentum. If both its speed and its mass are doubled, how much greater is its momentum? A) Two times. B) Four times. C) Eight times. D) Unchanged, the same.
February 19, 2012 by britches

physics
an ball of mass initially at rest fragments into two masses each of 1 kg moving with speed 0.6c. find the mass of original body
September 4, 2013 by gj

physics
A 400g glider moving to the right at 2 m/s collides elastically with a 500g glider moving in the opposite direction at 3 m/s. find the velocity of each glider? please show work so i can understand it! thanks
December 15, 2009 by mary ann

chemistry phyics HELP PLEASE STUCK
A 20.0 L tank contains helium at a pressure of 100 atm and a temperature of 30 degrees Celsius. A) what is the mass of the helium inside the tank?(HINT: the molar mas of He is 4.0 g/mol B) what would the mass of nitrogen (N2) be under the same conditions?
October 27, 2014 by nikkie

nucleus true facts
is the nucleus always found in the center of the cell? I know the nucleolus is located inside the center of the nucleus but is the nucleus alwasy found in the center of the cell? Short answere is no. The cell nucleus does not have to be in the exact center of the cell. It can...
October 4, 2006 by jamal

physics
The gravitational field strength at the surface of a certain neutron star is 1.34*10^12 N/kg. What would be the theoretical maximum height of a cylindrical granite column which could support its own weight without crushing when exposed to a field of this magnitude? (density of...
December 16, 2012 by adebiyi

physics
The gravitational field strength at the surface of a certain neutron star is 1.34*10^12 N/kg. What would be the theoretical maximum height of a cylindrical granite column which could support its own weight without crushing when exposed to a field of this magnitude? (density of...
December 16, 2012 by adebiyi

Science Question 1
How many helium atoms must undergo fusion at 100 million K in the helium flash? A.Two B.Three C.Four D.Six E.It varies with density At that temperature, three form carbon, and a fourth with the carbon forms oxygen. This is the main source of carbon and oxygen in the universe. ...
December 11, 2006 by Liz

Chemistry
A helium baloon has a volume of 28.9L, what is the mass of helium inside the ballon? what is the mass of the same volume of air it displaces? MM of air = 29.0g/mol, 25C (temperature) and 1 atm.
November 17, 2010 by Ashley

physics
On an air track, a 403.0 glider moving to the right at 2.30 collides elastically with a 501.0 glider moving in the opposite direction at 3.00 .Find the velocity of first glider after the collision
December 4, 2011 by Lindsay

PHYSICS HELP!
A compact car has a mass of 1400kg. Assume that the car has one spring on each wheel, that the springs are identical, and that the mass is equally distributed over the four springs. What is the spring constant of each spring if the empty car bounces up and down 1.9 times each ...
July 30, 2011 by CEO

Physics
A 0.9-kg block (mass m) and a second block (mass M) are both initially at rest on a frictionless inclined plane. Mass M rests against a spring that has a force constant of 12.2 kN/m. The distance d along the plane between the two blocks is 3.64 m. The 0.9-kg block is released...
November 9, 2014 by Anonymous

physics
Two particles, with identical positive charges and a separation of 2.60 x 10^-2 m, are released from rest. Immediately after the release, particle 1 has an acceleration a1 whose magnitude is 4.60 x 10^3 m/s^2, while particle 2 has an acceleration a 2 whose magnitude is 8.50 x ...
April 26, 2010 by kim

Algebra
If a worker wants to pack 200 newly harvested mangoes at average size of 3"x2" in delivery boxes .To optimize the cost and profit in packaging , the mangoes must be properly packed in boxes of similar sizes. To systemize counting , there must also be equal ...
August 17, 2014 by Claudette

MAth
If a worker wants to pack 200 newly harvested mangoes at average size of 3"x2" in delivery boxes .To optimize the cost and profit in packaging , the mangoes must be properly packed in boxes of similar sizes. To systemize counting , there must also be equal ...
August 17, 2014 by Claudette

physics
Point A is at a potential of +220 V, and point B is at a potential of -140 V. An -particle is a helium nucleus that contains two protons and two neutrons; the neutrons are electrically neutral. An -particle starts from rest at A and accelerates toward B. When the -particle ...
September 8, 2009 by kary

physics
Point A is at a potential of +250 V, and point B is at a potential of -150 V. An -particle is a helium nucleus that contains two protons and two neutrons; the neutrons are electrically neutral. An -particle starts from rest at A and accelerates toward B. When the -particle ...
January 12, 2011 by michelle

physics
A particle of mass 1 kg initially at rest is displaced along the x-axis by 127 meters in a time of 20 seconds. What is the net force acting on the mass?
December 6, 2011 by Anonymous

PHYSICS MAT
A 1.2 kg object moving at initial velocity 2.0m/s collides elastically with a stationary 0.5kg object horizontally. Calculate A) the velocity of each object after the collision. B) the impulsive force if the contact time is 0.3 s.
July 14, 2014 by THIYNES

Chemistry.
I need to know if these two statements are always true, AT; sometimes true, ST; or never true, NT. Thanks! 10. A mole of carbon atoms has a mass approximately three times as great as the mass of a mole of helium atoms. 11. The gram molecular mass of nitrogen is 14.0g.
March 19, 2009 by _ _ _ _ _ _.

Science Definitions
I need short definitions for these words be 4 2morrow. proton- neutron- electron- nucleus- atom- periodic table- atomic number- Go to www.dictionary.com. They have all of these words listed. Example how to find answers using Google: Word Proton http://www.google.com/search?...
August 23, 2006 by Kristin

Physics (please help!!)
The Crab pulsar (m=2.00x10^30 kg) is a neutron star located in the Crab Nebula. The rotation rate of the Crab pulsar is currently about 30.0 rotations per second, or 60.0pi rad/s. The rotation rate of the pulsar, however, is decreasing; each year, the rotation period increases...
April 15, 2011 by Abigail

physics
Two carts of equal mass, m = 0.280 kg, are placed on a frictionless track that has a light spring of force constant k = 51.9 N/m attached to one end of it. The red cart is given an initial velocity of v0 = 3.50 m/s to the right, and the blue cart is initially at rest. If the ...
October 27, 2008 by Sandhya

Honors Physics
A lumberjack (mass = 98 kg) is standing at rest on one end of a floating log (mass = 290 kg) that is also at rest. The lumberjack runs to the other end of the log, attaining a velocity of +3.1 m/s relative to the shore, and then hops onto an identical floating log that is ...
February 22, 2012 by Elizabeth

physics
Time standards are now based on atomic clocks. A promising second standard is based on pulsars, which are rotating neutron stars (highly compact stars consisting only of neutrons). Some rotate at a rate that is highly stable, sending out a radio beacon that sweeps briefly ...
December 11, 2008 by johnny

physics
12. If alpha particles are caused to fall through a potential difference of 1500 volts, determine their final speed if they were initially at rest. Alpha particles are Helium nuclei composed of two protons and two neutrons.
March 13, 2011 by ike

Chemistry
Hi, I am having trouble determining the correct answer for this question. Which one of the following decay modes has not been observed? A)neutron emission B)Positron emission C)Alpha emission D) electron capture I don't know what does it mean be "observed." If I had to guess ...
November 25, 2006 by Kyle

Physics
A car of mass m moving at a speed v1 collides and couples with the back of a truck of mass 3m moving initially in the same direction as the car at a lower speed v2. (Use any variable or symbol stated above as necessary.) (b) What is the change in kinetic energy of the car...
March 8, 2014 by Joe

Physics
A car of mass m moving at a speed v1 collides and couples with the back of a truck of mass 3m moving initially in the same direction as the car at a lower speed v2. (Use any variable or symbol stated above as necessary.) (b) What is the change in kinetic energy of the car...
March 10, 2014 by Joe

Physics
A car of mass m moving at a speed v1 collides and couples with the back of a truck of mass 3m moving initially in the same direction as the car at a lower speed v2. (Use any variable or symbol stated above as necessary.) (b) What is the change in kinetic energy of the car...
March 12, 2014 by Joe

Chemistry
The Goodyear blimps, which frequently fly over sporting events, hold approximately 1.9010^5 ft^3 of helium. If the gas is at 25 C and 1.0 atm, what mass of helium is in the blimp?
October 4, 2009 by Monica

physics
1. a particle A of mass 150g lies at rest on a smooth horizontal surface. a second particle B of mass 100g is projected along the surface with a speed of u m.s and collides directly with A. on collision the masses coalesce and moves on with a sped of 4 m.s . find the value of u?
April 25, 2011 by janell

Physics
In the railroad freight yard, an empty freight car of mass m rolls along a straight level track at 1.1 m/s and collides with an initially stationary, fully loaded boxcar of mass 4.3m. The two cars couple together upon collision. (a) What is the speed of the two cars after the ...
March 16, 2012 by Priyanka

Physics
A Goodyear blimp typically contains 4770 m3 of helium (He) at an absolute pressure of 1.10 x 105 Pa. The temperature of the helium is 274 K. What is the mass (in kg) of the helium in the blimp? A Goodyear blimp typically contains 4770 m3 of helium (He) at an absolute pressure ...
December 1, 2006 by maysam

physics
A moving 2.8 kg block collides with a horizontal spring whose spring constant is 215 N/m (see figure). The block compresses the spring a maximum distance of 11.5 cm from its rest position. The coefficient of kinetic friction between the block and the horizontal surface is 0.48...
November 23, 2010 by help

chemistry
Can someone help me with this? 1)What new element is formed if magnesium-24 is bombarded with a neutron and then ejects a proton? Write a balanced nuclear equestion for this transmutation. Is this beta decay? That's what I'm thinking, but I'm not sure. It ejects a proton, so ...
December 18, 2006 by Alexander

physics
A steel ball of mass m=5 g is moving at a speed of 250 m/s toward a large mass M=2.2 kg which is connected to a relaxed spring, as shown below. When the ball reaches the large mass it collides and bounces off without losing any kinetic energy. The large mass is connected to a ...
November 7, 2014 by joan

Physics
A 10kg ball A moving at a speed of 8m/s collides with a 20 kg ball B initially at rest. After The collision, the balls A and B move along the direction of 30 & 45 respectively with the initial direction of motion of A. Find the final speed of balls A and B?
July 15, 2011 by Shrawan

Chemistry
Calculate the mass of air in an air-filled tire and the mass of helium in a helium-filled tire. What is the mass difference between the two? Assume that the volume of the tire is 857 , that it is filled with a total pressure of 125 psi, and that the temperature is 26 . Also, ...
November 16, 2010 by Amanda

Physics
Mass 1 with a mass of 28.5 kg starts at rest at the top of a frictionless from a height of 17 meters. It then slides down the incline and moves over a horizontal frictionless surface and collides inelastically (head on) with mass 2 which is of unknown mass. After the ...
November 15, 2012 by Chelsea

Physics
A helium-4 atom falls from a height h into a tank of gaseous helium atoms at 300 K. What is h in meters if the temperature of the helium atoms remains at 300 K after the falling atom enters the tank? Details and assumptions The acceleration of gravity is −9.8 m/s2. As ...
April 2, 2013 by Crow

Physics URGENT!!!
Gayle runs at a speed of 9.00 m/s and dives on a sled, initially at rest on the top of a frictionless, snow-covered hill, that has a vertical drop of 20.0 m. After she has descended a vertical distance of 4.00 m, her brother, who is initially at rest, hops on her back, and ...
October 15, 2012 by Anonymous

physics
A cart of mass M1 = 4.00 kg and initial speed = 4.00 m/s collides head on with a second cart of mass M2 = 2.00 kg at rest. Assuming that the collision is elastic, find the speed of M2 after the collision. i keep getting 2.3 m/s what am i doing wrong?
March 7, 2008 by courtney

Are any tutors helping with Physics tonight? Help!
A cart of mass M1 = 6.00 kg and initial speed = 4.00 m/s collides head on with a second cart of mass M2 = 4.00 kg at rest. Assuming that the collision is elastic, find the speed of M2 after the collision.
February 15, 2011 by Megan

Are their any Physics tutors on here tonight?!
A cart of mass M1 = 6.00 kg and initial speed = 4.00 m/s collides head on with a second cart of mass M2 = 4.00 kg at rest. Assuming that the collision is elastic, find the speed of M2 after the collision.
February 15, 2011 by Megan

Physics
A 1.8-g balloon is filled with helium gas. When a mass of 4.8 g is attached to the balloon, the combined mass hangs in static equilibrium in midair. Assuming that the balloon is spherical, what is its diameter? (The density of helium is 0.179 kg/m3, and the density of air is 1...
November 7, 2011 by mymi

Physics
A balloon with a mass of 90 kg is filled with helium (density = 0.179 kg/m3). The balloon is spherical and has a diameter of 11.0 m. What is the maximum mass that can be attached to the bottom of this this helium balloon, for it to be able to fly? The density of air is 1.29 kg...
January 17, 2013 by Alphonse

physics
A proton that has a mass m and is moving at 250 m/s in the + direction undergoes a head-on elastic collision with a stationary oxygen nucleus of mass 16m. Find the velocities of the proton and the oxygen nucleus after the collision
May 7, 2012 by help please

physich
A proton that has a mass m and is moving at 280 m/s in the + direction undergoes a head-on elastic collision with a stationary oxygen nucleus of mass 16m. Find the velocities of the proton and the oxygen nucleus after the collision.
November 4, 2012 by Anonymous

Physics
A proton that has a mass m and is moving at 250 m/s in the + direction undergoes a head-on elastic collision with a stationary carbon nucleus of mass 12m. Find the velocities of the proton and the carbon nucleus after the collision. vp = m/s vcarbon = m/s
October 29, 2014 by Anonymous

Physics sorry for reposting but I really need help
An example of the neutron absorption reaction is . 1 0 n+10 5 B-->7 3 Li+ 4 2 He The rest masses of each particle in atomic mass units (u) are 1 0 n= 1 u 10 5 B=10 u 7 3 Li =7 u 4 2 He= 4 u where 1u=1.66x10^-27 kg. calculate Q Q= in MeV I have the same question please ...
May 8, 2013 by Amy

physics
A string is wrapped around a uniform disk of mass M = 1.6 kg and radius R = 0.10 m. (Recall that the moment of inertia of a uniform disk is (1/2)MR2.) Attached to the disk are four low-mass rods of radius b = 0.17 m, each with a small mass m = 0.6 kg at the end. The device is ...
July 31, 2014 by sara

Physics
A 26.0 g object moving to the right at 17.0 cm/s overtakes and collides elastically with a 10.0 g object moving in the same direction at 15.0 cm/s. Find the velocity of each object after the collision. a) 26.0 g object b) 10.0 g object
July 16, 2010 by Daisy

Physics
A lumberjack (mass = 98 kg) is standing at rest on one end of a floating log (mass = 245 kg) that is also at rest. The lumberjack runs to the other end of the log, attaining a velocity of +2.7 m/s relative to the shore, and then hops onto an identical floating log that is ...
November 14, 2010 by Jeffrey

physics
A lumberjack (mass = 98 kg) is standing at rest on one end of a floating log (mass = 200 kg) that is also at rest. The lumberjack runs to the other end of the log, attaining a velocity of +4.0 m/s relative to the shore, and then hops onto an identical floating log that is ...
July 19, 2013 by Anonymous

Physics
A 0.24-kg object traveling rightward at 3.5 m/s collides head-on and elastically with a 0.40-kg object traveling leftward at 2.1 m/s. (a) what are their velocities after collision? (b) If the objects are in contact for 0.010 s during collision, what is the magnitude of the ...
October 25, 2009 by Sandhu

Help me please with physics
A 25kg mass is on a level, rough surface where the force of friction is a constant 15 N. A horizontal applied force of 65 N acts on the mass. The mass is initially at rest. a) what speed does the mass have after 4.0 seconds? b) what speed does the mass have after being moved 2...
October 15, 2010 by Nicole

Physics
What gravitational force do yhe two protons in the helium nucleus exert on each other? There separation is approximately 1.0 fm. I know that 1 fm is 10^-15 m i didnt know if that was how you figured it out to get it to N?
June 15, 2009 by Sarah

physics
One object is at rest and another is moving. The two collide in a one-dimensional, completely inelastic collision. In other words, they stick together and move off with shared velocity. The speed of the object that is moving initially is 25 m/s. The masses of the two objects ...
September 29, 2014 by aithusa20

Physics I need help someone plz help out
An example of the neutron absorption reaction is . 1 0 n+10 5 B-->7 3 Li+ 4 2 He The rest masses of each particle in atomic mass units (u) are 1 0 n= 1 u 10 5 B=10 u 7 3 Li =7 u 4 2 He= 4 u where 1u=1.66x10^-27 kg. calculate Q Q= in MeV I have the same question please ...
May 8, 2013 by Amy

physics
A proton that has a mass m and is moving at 250 m/s in the + direction undergoes a head-on elastic collision with a stationary oxygen nucleus of mass 16m. Find the velocities of the proton and the oxygen nucleus after the collision i know i have to consider that both momentum ...
May 6, 2012 by CLUELESS

Physics
Consider three identical metal spheres, A, B, and C. Sphere A carries a charge of -8q. Sphere B carries a charge of +7q. Sphere C carries no net charge. Spheres A and B are touched together and then separated. Sphere C is then touched to sphere A and separated from it. Lastly...
August 28, 2007 by Mary

physics
trying to study but stuck on this problem. Two particles, with identical positive charges and a separation of 2.34 x 10-2 m, are released from rest. Immediately after the release, particle 1 has an acceleration a1 whose magnitude is 6.75 x 103 m/s2, while particle 2 has an ...
October 2, 2012 by antonio

Physics
Two pucks collide on an air hockey table. Puck A has a mass of 16 g and is initially traveling in the +x direction at 6.2 m/s. Puck B has a mass of 64 g and is initially at rest. After the pucks collide, puck A moves away at an angle of 58 above the +x axis, while puck B ...
February 25, 2011 by Mehreen

physics
The nucleus of a copper atom contains 29 protons and has a radius of 4.8*10^-15m. How much work (in electron volts) is done by the electric force as a proton is brought from infinity, where it is at rest, to the "surface" of a copper nucleus? I really got no clue to do it. Can...
May 7, 2008 by Shirley

Physics
An 67.6 kg object moving to the right at 38.7 cm/s overtakes and collides elastically with a second 48.9 kg object moving in the same direction at 19.2 cm/s. Find the velocity of the second object after the collision. Answer in units of cm/s
February 26, 2013 by colby

Physics
An 67.6 kg object moving to the right at 38.7 cm/s overtakes and collides elastically with a second 48.9 kg object moving in the same direction at 19.2 cm/s. Find the velocity of the second object after the collision. Answer in units of cm/s
March 5, 2013 by help

Physics
A cart of mass M1 = 4.00 kg and initial speed = 4.00 m/s collides head on with a second cart of mass M2 = 2.00 kg at rest. Assuming that the collision is elastic, find the speed of M2 after the collision. i keep getting the wrong answer please help me.I dont know what equation...
March 6, 2008 by josh g

Phsyics
Can someone give me some pointers on calculating the rest energy of a positron (a particle that has the same mass as an electron and equal but opposite charge) ? thanks The rest energy is equal to the mass times the speed of light squared.
May 24, 2007 by Jess

science
how do u put these in a concept map matter,family,periodic table,ionic bonding,solute,solvent,physical,chemical,double displacement,molecule,valence electrons,element,anion,synthesis,decomposition,concentration,dissociation,solution,neutron,period,proton,cation,metal,dilute,pH...
January 3, 2007 by brittany

science
1. the molar mass of helium is 4.00 g/mol. calculate the volume of 1 mol of helium at STP (T = 273, P = 1 atm) what is the density of helium at STP? 2. the density of an ideal gas is 1.35 kg/m^3. if the temperature is Kelvin and the pressure are both doubled, find teh new ...
April 23, 2008 by billystar

Physics
A wheel is rotating freely with an angular speed of 4840rad/s on a shaft whose moment of inertia is negligible. A second wheel, initially at rest and with 8 times the rotational inertia of the first is suddenly coupled to the same shaft. a) What is the angular speed of the ...
November 4, 2014 by Misaki

physics
a small block of mass M=0.050 kg is released from rest at the top (h=0.60 m) of the curved frictionless ramp shown above. The block slides down the ramp and collides with a larger block of mass 1.5M=0.075 kg at rest at the bottom of the incline. The larger block moves to the ...
November 13, 2011 by emilyy

physics
A 2.24 kg mass on a frictionless horizontal track is attached to the end of a horizontal spring whose force constant is 4.45 N/m. The mass is displaced 3.06 m to the right from its equilibrium position and then released, which initiates simple harmonic motion. How many times ...
December 2, 2012 by Emily

physics
A space traveler weighs 620 N on earth. What will the traveler weigh on another planet whose radius is three times that of earth and whose mass is twice that of earth?
January 30, 2012 by Anonymous

physics
A space traveler weighs 635 N on earth. What will the traveler weigh on another planet whose radius is three times that of earth and whose mass is twice that of earth?
October 4, 2012 by Donald

Physics
An electron is placed near a neutron. Which statement best describes the electrostatic force between them? a) there's no force between them since one is neutral b)there's a force of repulsion between them c)there's a force of attraction between them Isn't it a) because ...
April 5, 2008 by Andrea

physic
Two boxes are connected by by a massless string over a massless, frictionless pulley. Box 1 has a mass of m1 = 15.0 kg and is initially at rest at the bottom of a frictionless surface inclined at an angle θ = 30.0◦ above the horizontal. Box 2 has a mass of m2 = 10.0...
October 13, 2014 by Elvis

physic
Two boxes are connected by by a massless string over a massless, frictionless pulley. Box 1 has a mass of m1 = 15.0 kg and is initially at rest at the bottom of a frictionless surface inclined at an angle θ = 30.0◦ above the horizontal. Box 2 has a mass of m2 = 10.0...
October 14, 2014 by Elvis

Physics
The nucleus of the helium atom contains two protons that are separated by about 3.0 x 10-15 m. Find the magnitude of the electrostatic force that each proton exerts on the other
April 19, 2010 by Arnold Manguy

physics
What is the magnitude of the electrostatic force that the two protons inside the nucleus of a helium atom exert on each other? Why do atomic nuclei not simply explode?
September 12, 2012 by anna

physics
A dude is spinning a 1.0 kg mass on the end of a 1.5 meter string. He gets it spinning at a constant rate of 4.0 rev/sec. The string breaks such that the mass is thrown into projectile motion with an initial angle of 45 to the ground (assume that it is launched from ground ...
November 30, 2014 by hicham

physics
Spaceman Spiff sits just outside the Milky Way galaxy with a cup of liquid Helium which is at approximately 4K (-269 0C). He has with him a small sphere made entirely of copper which is at a temperature of 219K (-54 0C). After a certain amount of time his copper sphere comes ...
April 27, 2010 by gian

physics
1)7Be decays with a half-life of about 53 d. It is produced in the upper atmosphere, and filters down onto the Earth's surface. If a plant leaf is detected to have 300 decays/s of 7Be, how many days do we have to wait for the decay rate to drop to 13.6/s? Do not enter units. ...
April 15, 2008 by Sandhya

Physics
Will you check my work and help me with the last two problems please? A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed? -(12 kg/m/s) / 4kg=3m/s A ball is moving at 4 m/s and has a momentum of 48 kg m/s. What is the ball's mass? -(48kg/m/s) / (4m/s) =12 kg A 1-...
October 14, 2007 by Soly

physics
Will check my work and help me with the last two problems please? A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed? -(12 kg/m/s) / 4kg=3m/s A ball is moving at 4 m/s and has a momentum of 48 kg m/s. What is the ball's mass? -(48kg/m/s) / (4m/s) =12 kg A 1-kg ...
October 15, 2007 by Soly

physics
Point A is at a potential of +240 V, and point B is at a potential of -160 V. An α-particle is a helium nucleus that contains two protons and two neutrons; the neutrons are electrically neutral. An α-particle starts from rest at A and accelerates toward B. When the...
January 29, 2011 by Anonymous

vector and mass
A particle of mass m kg is acted on by two forces F1 and F2 with magnitudes 3root5 newtons and root5 newtons ad drections parallel to the vectors i+2j and i-2j respectively The particle is initially at a position given by vector 2i+j iv calculated the cartesian components of ...
July 15, 2006 by rav

Physics 112
Point A is at a potential of +270 V, and point B is at a potential of -130 V. An α-particle is a helium nucleus that contains two protons and two neutrons; the neutrons are electrically neutral. An α-particle starts from rest at A and accelerates toward B. When the...
January 18, 2011 by Anonymous

HELLO I NEED HELP AND NOBODY EVER HELPS ME.
1. the molar mass of helium is 4.00 g/mol. calculate the volume of 1 mol of helium at STP (T = 273, P = 1 atm) what is the density of helium at STP? 2. the density of an ideal gas is 1.35 kg/m^3. if the temperature is Kelvin and the pressure are both doubled, find teh new ...
April 23, 2008 by billystar

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