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September 20, 2014

Posts by physics


Total # Posts: 365

PHYSICS
density=mass/volume volume-mass/density
June 28, 2010

Physics
A boxer punches a 50 Kg bag. Just as his fist hits the bag, it travels at a speed of 7 m/s. As a result of hitting the bag, his hand comes to a complete stop. Assuming that the moving part of his hand weigh 5 Kg, calculate the rebound velocity and kinetic energy of the bag.
June 28, 2010

magnetic field
A square loop with resistance R=0.001 Ohms,mass 1.0 gram, and side length 1.0 m is falling into a region of uniform magnetic field. The magnetic field has strength 1 Gauss and is pointing out of the page. The speed of the loop just before it enters the region with the uniform ...
June 7, 2010

electric fields *easy
A charged particle is at the origin of coordinates. The particle produces an electric field of 4 kN/C at the point with position vector 36 cm. At what location does the field have the value 1 kN/C? Ans: 72 cm Could someone please explain to me what equation I would use and how...
June 5, 2010

PHYSICS
A long, straight wire lies on a horizontal table and carries a current of 1.45 µA. In a vacuum, a proton moves parallel to the wire (opposite the current) with a constant speed of 3.00 104 m/s at a distance d above the wire. Determine the value of d. Ignore the magnetic ...
May 26, 2010

Right Hand Rule
Consider an electron near the Earth's equator. In which direction does it tend to deflect if its velocity is directed in each of the following directions? (a) downward: WEST (b) northward . (c) westward d) southeastward I go the first one right using the right hand rule ...
May 21, 2010

Physics
The inner conductor of a coaxial cable has a radius of 0.900 mm, and the outer conductor's inside radius is 5.00 mm. The space between the conductors is filled with polyethylene, which has a dielectric constant of 2.30 and a dielectric strength of 18E6 V/m. What is the ...
May 13, 2010

PHySics
I understand now, thank you.
May 12, 2010

PHySics
A 1.63 nF parallel-plate capacitor is charged to an initial potential difference ΔVi = 100 V and then isolated. The dielectric material between the plates is mica, with a dielectric constant of 5.00. (a) How much work is required to withdraw the mica sheet? Work = .5CV^2...
May 12, 2010

PHYSICS
awesome thanks, that's the correct answer. I was using the wrong conversion. :)
May 12, 2010

PHYSICS
A 4.00 µF capacitor is connected to a 18.0 V battery. How much energy is stored in the capacitor? This should be a relatively easy problem yet, I can't get it. Isn't it just E=.5*C*V^2
May 12, 2010

Physics
I have solved this problem.
April 29, 2010

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 6.40 m/s. The wad of putty sticks to the block. How high does the putty-block system rise above the original ...
April 29, 2010

Physics
A 0.409 kg block is attached to a horizontal spring that is at its equilibrium length, and whose force constant is 19.5 N/m. The block rests on a frictionless surface. A 0.0500 kg wad of putty is thrown horizontally at the block, hitting it with an initial speed of 2.32 m/s ...
April 22, 2010

Physics
A 95 kg astronaut and a 1500 kg satellite are at rest relative to the space shuttle. The astronaut pushes on the satellite, giving it a speed of 0.15 m/s directly away from the shuttle. Seven-and-a-half seconds later the astronaut comes into contact with the shuttle. What was ...
April 22, 2010

Physics
this is a repeat of the question before it.
April 22, 2010

Physics
A 0.135 kg ball is dropped from rest. If the magnitude of the ball's momentum is 0.730 kg·m/s just before it lands on the ground, from what height was it dropped?
April 22, 2010

Physics
A 0.135 kg ball is dropped from rest. If the magnitude of the ball's momentum is 0.730 kg·m/s just before it lands on the ground, from what height was it dropped?
April 22, 2010

Physics
In order to keep a leaking ship from sinking, it is necessary to pump 15.0 {\rm lb} of water each second from below deck up a height of 2.00 {\rm m} and over the side.What is the minimum horsepower motor that can be used to save the ship? What is the minimum horsepower motor ...
April 8, 2010

physics
A wire 28 cm long is parallel to a 0.36 T uniform magnetic field. The current through the wire is 4.5 A. What force acts on the wire? What equation do you use? I tried F= ILBsin(90) and that didn't work!
March 23, 2010

11th grade
A wire 28 cm long is parallel to a 0.36 T uniform magnetic field. The current through the wire is 4.5 A. What force acts on the wire? What equation do you use?
March 23, 2010

Gweedo8
a man stand on a 100 m cliff and throws a rock with speed of 40ms at 42degrees above horizontal. what time before rock hits ground. the horizontal distance the rock traveled from base of cliff.? my answer is 4.08 sec before rock hits ground 81.6 m distance traveled from base ...
January 29, 2010

Paul
Determien teh mass of the Sun using the known value for the period of the Earth and its distance from the Sun. I do not remeber how to do this F = ma = Fg = GmM/r^2 Period of earth 3.16 E 7 s radius earth to moon = 1.5 E 11 m
December 22, 2009

Phys sci
ITS C
December 8, 2009

Physics
I could also just do sheet of glass
October 24, 2009

Physics
How much pressure is required to crack an egg under water Is there like a table I could look at that has values for how much pressure things can withstand before cracking
October 24, 2009

Physics (Please)
I'm confused and am hoping someone could help me understand energy can neither be created nor destroyed... great... so in physics classes we can set up problems and stuff were KEo + PEo = KE + PE Energy intial equals energy final sense energy is conserved but then when ...
October 19, 2009

Physics
i was woundering if you could point in the right direction i'm looking for very easy physics topics that makes use of the law of sines or the law of cosines Thanks
October 19, 2009

physics
when an object is rotating in a circle and the only force is acting on it is friction how is force of friction vector pointing towards the circle because an object in circular motion is traveling in that direction, it's accelerating towards the center of the circle, but ...
October 12, 2009

Physics
How am I doing this problem wrong On a strange, airless planet, a ball is thrown downward from a height of 17 m. The ball initally travels at 15 m/s. If the ball hits the ground in 1 s, what is this planet's gravitational acceleration? by definition of acceleration a = (v...
October 11, 2009

Physics
Ok work... work = net force parallel to displacement lets say something was pushed up a ramp at a constant velocity and you were asked how much work was done by pushing the block well the forces parellel to the displacement is the x component of gravity friction opposing ...
October 9, 2009

physics egg drop
What is the best idea for an egg drop project. it has to survive a 5 meter drope without craking or breaking open.(grade A egg wich is a bog egg). The desinge or idea has to be able to be opened and have the egg in hand within 10 sec, so packing it into boxes over and over ...
October 6, 2009

Physics
I agree with this and see were it comes from net force = (delta p)/t so momentum is conserved when net force equals zero... net force = (delta p)/t 0 = (delta p)/t however the following is not true 0 = (delta p)/t = P - Po were p is momentum and Po is used to indicate inital ...
October 3, 2009

Physics
momentum equals = mass (velocity) yet for problems I end up using this P = m (delta v) what allows us to simply put the delta infront of the v to find the momentum?
October 3, 2009

Physics
I keep on getting the wrong answer I don't know if there is even static friciton in this problem in the begining before the rope snaps or not and if so if it must be equal to the Mu they give because there is only one but you can't have the same values for both ...
September 25, 2009

Physics
I keep on getting the wrong answer I don't know if there is even static friciton in this problem in the begining before the rope snaps or not and if so if it must be equal to the Mu they give because there is only one but you can't have the same values for both ...
September 25, 2009

Physics
I'm not sure how to do this problem A .40 kg ball is thrown with a speed of 10 s^-1 m at an angle of 30 degrees. (a) What is its speed at its highest point, and (b) how high doe it go? (Use conservation of energy.)
September 24, 2009

Physics
I'm not sure how to do this problem A 145-g baseball is droppexc from a tree 12.0 m above the ground. (a) Wtih what speed would it hit the ground if air resistance could be ignored? (b) If it actually hits the ground with a speed of 8.00 s^-1 m, what is the average force ...
September 24, 2009

Physics
A small block of mass m rests on the sloping side of a triangular block of mass M which itself rests on a horizontal table. Assuming all surfaces are frictionless, determine the magnitude of the force ->F that must be applied to M so that m remains in a fixed position ...
September 23, 2009

Physics
Mass m_A rests on a smooth horizontal surface, m_B hangs vertically. If m_A=15.0 kg and m_B=3.0 kg in the figure , determine the magnitude of the acceleration of each block.Enter your answers numerically separated by a comma. If initially m_A is at rest 1.300 m from the edge ...
September 23, 2009

Physics!
The cable supporting a 2100kg elevator has a maximum strength of 2.19×10^4 N. What maximum upward acceleration can it give the elevator without breaking?
September 23, 2009

Physics
One car has twice the maqss of a second car, but only half as much kiinetic energy. When both cars increase their speed by 7.0 s^-1 m, they then have the smae kinetic energy. What were the original speeds of the two cars? I got -16 or 2.4
September 22, 2009

Physics
I gues I'm looking at this the wrong way i do not understand the work you do to get to the answer Question: Find the air velocity of a plane that must have a realtive ground velocity of 250.0 h^-1 km norht if it encounters a wind pushing it toward the northeast at 75 h^-1 ...
September 18, 2009

phys need help
I typed in the answer for the direction (85 and 175) and they are both wrong according to the problem. I want to try 4.8 degrees since it says east of south, but I don't know though.
September 15, 2009

phys
An airplane is heading due south at a speed of 590 km/h. If a wind begins blowing from the southwest at a speed of 65.0 km/h (average). Calculate magnitude of the plane's velocity, relative to the ground. Calculate direction of the plane's velocity, relative to the ...
September 15, 2009

phys
At t= 0, a particle starts from rest at x= 0, y= 0, and moves in the xy plane with an acceleration ->a = (4.0ihat+ 3.0jhat)m/s^2. Assume t is in seconds. Determine the position of the particle as a function of time t. Express your answer in terms of the unit vectors ihat ...
September 15, 2009

physics need to check
I get 131.18 degrees and its wrong. I don't know what I am doing wrong.
September 15, 2009

physics
Let ->V1= -6.1 ihat + 8.0 jhat and ->V2 = -4.8 jhat + 4.2 ihat. Determine the direction of ->V1 counterclockwise from the +x direction Determine the direction of ->V2 counterclockwise from the +x direction
September 15, 2009

physics
If Vx= 8.00 units and Vy= -6.40 unis, determine (a)the magnitude and (b)direction of ->V(vector) b) theta= ______ degrees below the positive x-axis.
September 14, 2009

physics
please h t t p : / / w w w . j i s k h a . c o m / d i s p l a y . c g i ? i d = 1 2 5 2 8 9 5 3 6 7
September 14, 2009

physics
this is from that white book that i'm also using... the odd answers in the book are in the back in which this problem is one I belive
September 14, 2009

physics
At t= 0, a particle starts from rest at x= 0, y= 0, and moves in the xy plane with an acceleration ->a (vector) = (4.0ihat+ 3.0jhat)m/s^2. Assume t is in seconds. Determine the x component of velocity as a function of time t. Determine the y component of velocity as a ...
September 13, 2009

physics
can you walk me through this problem At what distance from teh Earth will a spacecraft on the way to the Moon esperience zero net force due to these two bodies because the EArth and Mon pull with equal and opposite forces? mass of earth = m1 = 5.98 E 24 kg mass of moon = m2 = ...
September 13, 2009

Physics
I have no idea how to do this problem At what distance from teh Earth will a spacecraft on the way to the Moon esperience zero net force due to these two bodies because the EArth and Mon pull with equal and opposite forces? there\'s no data in the question to use
September 13, 2009

physics
we can say that the force of gravity is equal to mass times acceleration were the acceleration is equal to gravity sense gravity is an acceleration because of newtons second law force = mass times acceleration hence Fg = mass times acceleration Fg = mass times gravity Fg = mg ...
September 12, 2009

physics
Calculate the acceleration due to gravity on the moon. The moon\'s radius is about 1.74 E 6 m and its mass is 7.35 E 22 kg ok aparently there\'s an easier way to do this I applied Newtons second law in the radial direction net force radial = m (radial acceleration) = ...
September 12, 2009

physics
If this question is asking for the normal force i got 100 n but i\'m not sure that is what it is asking for
September 11, 2009

physics
A rope of negligible mass passes over a puley of a negligible mass attached to the ceiling. One end of the rope is held by stdent A of mass 70 kg who is at rest on the floor. The opposite end of the rope is held by student B of mass 60 kg who is suspended at rest above the ...
September 11, 2009

Physics
not sure what the force of tension is equal to in this problem
September 6, 2009

Physics
Tarzan plans to corss a gorge by swinging in an arc form a hanging vine. If his arms are capable of exerting a force of 1400 N on the rope, what is the maximum speed he can tolerate at the lowest point of his swing? his mass is 80 kg and the vine is 4.8 m long. Ok If i\'m ...
September 6, 2009

physics
centripetal acceleration= friction m*w^2 r = mu*mg changing 50 rpm to rad/sec mu=w^2 r/g=(50*2PI/60)^2 * .12 which is not your answer. Check my thinking. ok I thought centripetal force was equal to m ac were ac is the centripetal acceleration which is equal to v^2 divided by r...
September 5, 2009

Physics
A coin is placced 12.0 cm from the axis of a roatating turntable of variable speed. When the speed of the turntable is slowly incraeased, teh coin remains fixed on the turntable until a rate of 50 rpm is reached at which point the coin slides off. What is the coefficent of ...
September 5, 2009

Physics
A coin is placced 12.0 cm from the axis of a roatating turntable of variable speed. When the speed of the turntable is slowly incraeased, teh coin remains fixed on the turntable until a rate of 50 rpm is reached at which point the coin slides off. What is the coefficent of ...
September 5, 2009

physics
Net Force Radial = m a radial = F radial = Ffr ma radial = Us Fn ma radial = Us m g cancel out mass a radial = Us g a radial = r^-1 v^2 r^-1 v^2 = Us g Us = (rg)^-1 V^2 don\'t see what I did wrong
September 5, 2009

physics
A coin is placced 12.0 cm from the axis of a roatating turntable of variable speed. When the speed of the turntable is slowly incraeased, teh coin remains fixed on the turntable until a rate of 50 mph is reached at which point the coin slides off. What is the coefficent of ...
September 5, 2009

physics
so there is no static friction when a block is just sitting there and not moving with no applied force?
September 3, 2009

physics
what is the equal and opposite force the force of friction like if a block is at rest on a table static friction is stil exerted by the table onto the block keeping it from moving what is the equal and opposite force of this force?
September 3, 2009

Physics
A model rock is shot into the air. Once it starts to fall a parachute is deployed. Draw a free body diagram of the rocket with the parachute deployed ok well there is gravity does the parachute exert a force upward? onto what? what do i call this force?
August 28, 2009

Physics
yay i got it right thanks!
August 26, 2009

Physics
a mass (m1) on a smooth horizontal surface, connected by a thin cord that passes over a pulley to a second block (m2), which hangs vertically. If the acceleration is .098 m/s^2 and m1 is 1.0 kg how much must m1 must be to keep it at this acceleration I got 99 kg could you ...
August 26, 2009

Physics
oh wow so I\'m not sure how to do this if the net force in the y direciton is zero...
August 25, 2009

Physics
wait so if downards was negative the force of gravity on the first block would be -85 N the force of gravity on the seocnd block is - 30 N for problem (a) and the force of tension is equal and opposite to the force of gravity on the second block and is 30 N net force in y ...
August 25, 2009

Physics
I have a question 26. A box weighing 85 N rests on a table. A rope tied to the box runs vertically upward over a pully and a weight is hung form the other end. Detrmine the force that the table exerts on the box if the weight hanging on the other side of the pully weighs (a) ...
August 25, 2009

Physics
Is mass the one and only thing that produces a gravitional force???
August 17, 2009

physics
take a satalite going around the earth... what allows us to say net force (radial) = Fg = Fr = ma were the Fg is the force of gravity exerted on the satalite were Fr is radial force and ma is the mass and acceleration of the satalite ok I understand newtons second law but what...
August 17, 2009

physics
"The actual value of computed g, assuming no drag, also varies somewhat over the earth's surface due to the earth's spin (which causes a latitude-dependent centrifugal force to get subtracted), lack of a perfect spherical shape of the earth, and the proximity of ...
August 13, 2009

physics
Hi i'm doing that lab were you attach a weight to a tape which is also through a timer that puts marks on the tape at a given time interval ok I'm asked why is gravity different than on Earth? I don't rember the physics answer behind it I remeber Fg = G((m1 m1)/r^2...
August 13, 2009

physics
ok i saw the responses thanks still a little bit confused ok what variable is different or varaies in the sitations were you to walk say down a hill and feel that it is easier and when walking up a hill which is harder
August 12, 2009

physics
ok i'm doing a lab were walking different displacements I observed that the displacements were on different grades of steepness this would decrease the coefficent of kinetic friction?
August 12, 2009

physics
does the slope of a distance vs. time graph show the average velocity or the instaneous velocity I'm asked the question and don't know which one. I believe that it would be the instaneous value because the slope is refering to one point on the graph... not sure though
August 12, 2009

physics
hey wow thanks!!! I acutally understood just kind of werid because our book hasn't mentioned energy yet but I know about it from just regualr old physics I'm taking ap this year and doing the first chapters in order and it hasn't mentioned anything about energy yet...
August 11, 2009

physics
ok a person is holding onto a piece of string at the end of the string is a ball the person whrils it around in a circle i've been asked what's the mininum value of at the top of the circle (this is swung around in a verticle circle) what is the mininum value the ...
August 11, 2009

physics (geometry bit)
How to prove this? Similar triangles. Notice the upper angle in that photo is a right angle (ramp to Fn), yes and i agree right anlge in which the angle of Fn to the vertical is an angle complement to Fp and the vertical. ok so your saying that... angle Fn Fw is complement to ...
August 11, 2009

physics (geometry bit)
ohh ok um Fw is the gravity and Fp is the x component and Fn is the y component??? how come the x component is drawn in a weired location but we got the triangle now thanks!!!
August 11, 2009

physics (geometry bit)
what's fw and Fp
August 11, 2009

physics (geometry bit)
ha ha i copied the lnik instead of clicking on it i got it thanks
August 11, 2009

physics (geometry bit)
when i click on your link it bring me here h t t p : / / ww w . a n g e l f i r e . l yc o s . c o m / d o c / im ag e s / r l o a d b l oc k . j p g i noticed a different adress then the link
August 11, 2009

physics (geometry bit)
not for me =[ look... h t t p : / /i m g1 3 2 . i ma g e s h a c k. u s / i m g1 3 2 / 9 1 3 7 /c a p tu r e t q i. j p g could you try image shack upload (link below) I don't know why it wouldn't let me see it i captured the screen when i clicked on the link it's ...
August 11, 2009

physics (geometry bit)
link didn't got to image
August 11, 2009

physics (geometry bit)
your image didn't work
August 11, 2009

physics
i have a question in my book centripetal acceleration = r^-1 v^2 ok I agree but in my book acceelration is labeled as a vector but yet the velocity is not... Why?
August 10, 2009

physics
thanks for the help earlier just got a question I'm taking AP Physics B this year does that mean next year I would Take AP Physics C??? I don't know if the material in C convers the same material plus the additional calculus material or what??? Could I take AP Calculus...
August 9, 2009

physics
I just would like to make sure of something an object experiances a drag force when it travels through a medium like air or water... so dosen't every thing experience a drag force that is in motion because its moving through air?? So like if a person was walking do they ...
July 31, 2009

physics
also I was always told to use this equation when the velocity is small through the medium Fd = -bv were this is just a proportion also that other formula that is suppose to be used when there is a high velocity Fd = 2^-1 p v^2 A Cd v Ok what is exactly meant by high and low ...
July 31, 2009

physics
so I got a question about projectile motion take the example of shooting of a plastic air rocket into the air and asked to predict its landing point and how high it goes... ok I know how to do this... the thing is now were not neglecting air resistence and I don't know ...
July 31, 2009

physics
I don't see how this relationship works Fn sin theta = r^-1 m v^2 or more like why it works??? my text goes on to prove tan theta = (rg)^-1 v^2 which I understand how to rearange I just don't get where the first relationship comes from Fn sin theta = r^-1 m v^2 i get ...
July 30, 2009

physics
ok if a car is going around a bank curve my book is telling me there is an ideal spead were no friction is required at all for it to complete the banked turn it says that this occurs when the horizontal component of the normal force is equal to the radial acceleration why?
July 30, 2009

physics
I'm trying to rearange this equation for Mu s That is the greek letter Mu subscript s... the static coeficent of friction m2 = m1 sin theta - Mu s m1 cos theta ok I got this Mu s = -((m1 cos theta)^-1 (m2 - m1 sin theta)) ok I know that sin over cosine is tangent but I ...
July 30, 2009

Tj
a wire has a resistance of 10 ohms. The length of the wire is doubled, and its radius is also doubled. What is the new resistance?
July 21, 2009

physics
a block (mass m1) on a smooth horizontal surface, connected by a thin cord that passes over a pulley to as second block (m2), which hangs vertically. Ignore friction and the masses of the pulley and cord. If m1 = 13.0 kg and m2 = 6.0 kg determine the accleeration of each block...
July 14, 2009

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