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April 20, 2014

Homework Help: Science: Physics

Recent Homework Questions About Physics

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Physics
the scale is in kilograms, thx for helping me understand :)
Monday, March 17, 2014 at 7:30pm

Physics
A pump is required to lift a mass of 750kg of water per minute from a well of depth 13.2m and eject it with a speed of 17.4m/s. A) How much work is done per minute in lifting the water? B) How much in giving the water the kinetic energy it has when ejected? C) What must be the...
Monday, March 17, 2014 at 7:26pm

Physics
weight = m g normal force down on floor N= m g+Fsin 28 friction force back = .25 N so F cos 28 = friction force back (a) F = friction force back / cos 28 force component in direction of motion = F cos 28 Newtons d = 4.1 meters so (b) Win = 4.1 F cos 28 Joules (c) -4.1 F cos 28...
Monday, March 17, 2014 at 7:16pm

Physics
A factory worker pushes a 29.2kg crate a distance of 4.1m along a level floor at constant velocity by pushing downward at an angle of 28 degrees below the horizontal. The coefficient of kinetic friction between the crate and floor is 0.25. (a) What magnitude of force must the ...
Monday, March 17, 2014 at 7:04pm

help ms sue lang arts
For Questions 1–6, read the play excerpt below and answer the questions that follow. Jaws of the Water ACT TWO At rise we see DAD, TINA, and MARK rushing in and out of the living room. Each enters carrying important items—such as sleeping bags, rain gear, and ...
Monday, March 17, 2014 at 7:04pm

Physics
You are welcome :)
Monday, March 17, 2014 at 7:01pm

Physics
If your scale reads in grams or kilograms, that is mass assuming you do this on earth without acceleration (do not do it while in free fall before opening your parachute) If your scale reads in pounds, that is really force, not mass. Convert the pounds to kilograms.
Monday, March 17, 2014 at 6:49pm

Physics
I need help with my lab, it's telling me to measure the mass of cup 1, but i don't understand how to measure it... I have a digital scale does that measure mass? or is there a certain equation to measure it?
Monday, March 17, 2014 at 6:15pm

11th grade Physics
146216
Monday, March 17, 2014 at 6:02pm

physics
THINK !!! B goes up when current goes up, that is what causes B gets weak when you get away from wire of course. so the second choice
Monday, March 17, 2014 at 5:40pm

Physics
Thank you!
Monday, March 17, 2014 at 5:37pm

physics
The magnitude of the magnetic field produced by a long straight current-carrying wire is: proportional to both the current in the wire and the distance from the wire proportional to the current in the wire and inversely proportional to the distance from the wire inversely ...
Monday, March 17, 2014 at 5:26pm

Physics
short string ----> higher frequency !!! f = k/L so (5/4) 440 = 550
Monday, March 17, 2014 at 5:20pm

physics
P = angular momentum = I omega I1 = (1/2) m r^2 = (1/2)(4.7)(.17)^2 = .0679 P1 = (.0679) 2 pi (1.8) I2 = I1 + (1/2)(3.1) (.065)^2 = .0679 + .00655 = .0744 P2 = P1 so .0744 (2 pi)(rps) = .0679 * 2 pi *1.8 rps = 1.64 revs/s so I agree with you wholeheartedly
Monday, March 17, 2014 at 5:17pm

scince i try i have no idea
Google them for example force definition physics yields among other links: http://physics.info/newton-first/
Monday, March 17, 2014 at 4:49pm

physics
A potter's wheel is rotating around a vertical axis through its center at a frequency of 1.8rev/s . The wheel can be considered a uniform disk of mass 4.7kg and diameter 0.34m . The potter then throws a 3.1kg chunk of clay, approximately shaped as a flat disk of radius ...
Monday, March 17, 2014 at 4:02pm

Physics
Suppose you pluck a string on a guitar and it produces the note A at a frequency of 440 Hz. Now, you press your finger down on the string against one of the frets, making this point the new end of the string. The newly shortened string has 4/5 the length of the full string. ...
Monday, March 17, 2014 at 3:56pm

Physics
Smoking causes blood vessels to constrict. If the average blood vessel radius of a smoker decreases 7.6% and the body increases blood pressure to maintain a constant flow. Calculate the needed percent increase in pressure.
Monday, March 17, 2014 at 3:19pm

Physics
An artery supplying heat muscle with blood is occluded to 13.9% of its original radius by a clot. By what percent is the blood flow through this artery reduced.
Monday, March 17, 2014 at 3:18pm

Physics
Neglecting the pressure drop due to resistance, calculate the blood pressure in mmHg in an artery in the brain 32 cm above the heart. The pressure at the heart is 120mmHg and the density of blood is 1.05g/cm3.
Monday, March 17, 2014 at 3:16pm

Physics
A full term fetus may have a mass of 3.3 kg . If the entire weight of the fetus rests momentarily on the mother's bladder, supported on an area of 78.8 cm2 calculate the pressure exerted in mmHg.
Monday, March 17, 2014 at 3:15pm

physics
What is the ratio of the speed of sound in air at 0°C to the speed at 100°C?
Monday, March 17, 2014 at 3:02pm

physics
A convex spherical mirror has a focal length of -20 cm. An object is placed 30 cm in front of the mirror on the mirror's axis. Where is the image located? Answer 12 cm in front of the mirror 60 cm behind the mirror 60 cm in front of the mirror none of the given answers
Monday, March 17, 2014 at 2:56pm

Physics
http://www.jiskha.com/display.cgi?id=139​5061565
Monday, March 17, 2014 at 1:58pm

Physics
Hmmm. What's 92% of 750?
Monday, March 17, 2014 at 1:58pm

Physics
I did this already.
Monday, March 17, 2014 at 1:57pm

Physics
A high efficiency natural gas furnace is 92% efficient. How many joules of output energy will 750kJ of input fuel provide? Please help! Thank you.
Monday, March 17, 2014 at 1:57pm

Physics
F = k Q1 Q2 / d^2 = 9*10^9 * 1.6*10^-19*1.6*10^-19 / (26.1*10^-30) = .882 * 10^1 = 8.82 Newtons
Monday, March 17, 2014 at 1:55pm

physics
NMNMNMN
Monday, March 17, 2014 at 12:33pm

Physics
At the point of fission, a nucleus of 235U that has 92 protons is divided into two smaller spheres, each of which has 46 protons and a radius of 5.11 ✕ 10-15 m. What is the magnitude of the repulsive force pushing these two spheres apart?
Monday, March 17, 2014 at 10:57am

Physics
A linear spring of stiffness k is designed to stop the 20-Mg railroad car traveling at 8 km/h within 400mm after impact. Find the smallest value of k that will produce the desired result.
Monday, March 17, 2014 at 8:45am

physics
speedofWave=frequency*wavlength
Monday, March 17, 2014 at 7:07am

physics
987
Monday, March 17, 2014 at 5:15am

physics
the frequency of wave A is 250 hertz and the wavelength is 30 cm. the frequency of wave B is 260 hertz and the wavelength is 25 cm. which is a faster wave?
Monday, March 17, 2014 at 2:03am

physics
. A train starts from rest and accelerates uniformly, until it has traveled 3.7 km and acquired a velocity of The train then moves at a constant velocity of for 410 s. The train then slows down uniformly at until it reaches a halt. What distance does the train travel while it ...
Monday, March 17, 2014 at 1:57am

Physics please help?????
I got the complete equation 1/2*k*y^2 - m*g*y - m*g*3h0 and solved for y, and got 0.330 and its correct. Thanks.
Monday, March 17, 2014 at 1:08am

Physics
fdgfd
Monday, March 17, 2014 at 12:47am

PHYSICS
asd
Monday, March 17, 2014 at 12:36am

Physics please help?????
distance block moves down = h0 + .198 loss of potential energy by block = .540 ( 9.81 ) (h0+.198) gain of potential energy by spring = (1/2)(320)(.198). This is energy gained by spring and lost by block. so .540(9.81)(h0+.198) = (1/2)(320)(.198) solve for h0 then do it for 3 h0
Monday, March 17, 2014 at 12:21am

Physics
sdfsf
Monday, March 17, 2014 at 12:13am

Physics please help?????
A 540 g block is released from rest at height h0 above a vertical spring with spring constant k = 320 N/m and negligible mass. The block sticks to the spring and momentarily stops after compressing the spring 19.8 cm. How much work is done (a) by the block on the spring and (b...
Sunday, March 16, 2014 at 11:58pm

physics
poop
Sunday, March 16, 2014 at 11:38pm

Physics
Three point charges of 8 C, 3 C, and -5 C, are locate at the top, bottom left, and bottom right corners respectively of an equilateral triangle of side 1Å. Find the magnitude and direction of the net force on the 3 C charge.
Sunday, March 16, 2014 at 11:08pm

physics
m*g = 15.7 * 9.8 = 153.9 N. = Wt. of block. Fn = 153.9*cos12.1 = 150.4 N.
Sunday, March 16, 2014 at 9:56pm

Physics
PEmax=mg*hmax = 28*9.8 * 159=43,630 J. = KEmax @ bottom of hill with no friction. KE = 14*31.3^2 = 13,716 J. Energy lost = 43,630 - 13,716=29,914 J.
Sunday, March 16, 2014 at 9:16pm

physics
Light enters a container of liquid at an angle of 35° to the normal; the refracted beam makes an angle of 21° with the normal. Calculate the index of refraction of this liquid.
Sunday, March 16, 2014 at 8:40pm

physics-impulse
Impulse = 2*m*V*cos45
Sunday, March 16, 2014 at 8:05pm

physics
Singapore. Looked at the results after the quiz and got it wrong when i put New Zealand.
Sunday, March 16, 2014 at 8:03pm

Physics
Energy = m*g*h.
Sunday, March 16, 2014 at 7:57pm

Physics
m*g = 295 * 9.8 = 2891 N. = Wt. of box. = Fn = Normal force. Fs = u*Fn = 0.2 * 2891 = 578.2 N. = Force of static friction. Fe-Fs = m*a Fe - 578.2 = m*0 = 0 Fe = 578.2 N. = Force of engine. Energy=Work = Fe*d = 578.2 * 2.8=1619 J.
Sunday, March 16, 2014 at 7:50pm

Physics
A 540 g block is released from rest at height h0 above a vertical spring with spring constant k = 320 N/m and negligible mass. The block sticks to the spring and momentarily stops after compressing the spring 19.8 cm. How much work is done (a) by the block on the spring and (b...
Sunday, March 16, 2014 at 7:38pm

physics
a=(V^2-Vo)/2d = (0-20^2)/1000=-0.4 m/s^2 F = m*a = 10000 * -0.4 = -4,000 N.
Sunday, March 16, 2014 at 7:21pm

Physics
A 2.2 C charge is located on the x-axis at x = -1.5 m. A 5.4 C charge is located on the x-axis at x = 2.0m. A 3.5 C charge is at the origin. Find the net force acting on the 3.5 C charge.
Sunday, March 16, 2014 at 6:54pm

Physics
A 2.2 C charge is located on the x-axis at x = -1.5 m. A 5.4 C charge is located on the x-axis at x = 2.0m. A 3.5 C charge is at the origin. Find the net force acting on the 3.5 C charge.
Sunday, March 16, 2014 at 6:54pm

physics
A force of 15N acts in the forward direction on a carton of 3kg. Suppose a friction force of 6N opposes the carton motion. Find the following: 1) the net force 2) the acceleration of the carton
Sunday, March 16, 2014 at 6:20pm

Physics
A 2.2 uC charge is located on the x-axis at x = -1.5 m. A 5.4 uC charge is located on the x-axis at x = 2.0m. A 3.5 uC charge is at the origin. Find the net force acting on the 3.5 C charge.
Sunday, March 16, 2014 at 6:15pm

physics
calculate the heat given up when 0.1kg of steam at 100¡ã© condenses to h20 at 40¡ã©(s.l.h of vaporisation = 2.2¡Á10^6) (c=4200)
Sunday, March 16, 2014 at 5:13pm

PHYSICS
check the related questions below
Sunday, March 16, 2014 at 4:49pm

physics
25.2 m
Sunday, March 16, 2014 at 4:42pm

PHYSICS
A 0.380 kg pendulum bob passes through the lowest part of its path at a speed of 2.03 m/s. What is the tension in the pendulum cable at this point if the pendulum is 83.1 cm long? When the pendulum reaches its highest point, what angle does the cable make with the vertical? ...
Sunday, March 16, 2014 at 4:06pm

Physics
r = .14 meter w = omega, angular rate in radians/sec Ac = w^2 r F = m Ac 4*10^-11 = 3 *10^-16 (w^2)(.14) w^2 = 9.52 * 10^5 = 95.2 * 10^4 w = 9.76 * 10^2 radians/second rev = 2 pi radians 976 rad/s * 1 rev/2pi rad = 155 rev/s
Sunday, March 16, 2014 at 3:46pm

physics
initial momentum = 28000 u final momentum = (m+28000) v so 28000 u = m v + 28000 v initial ke = 14000 u^2 final ke = (14000+.5m)v^2 (14000+.5m)v^2 = .8 (14000 u^2) (14000+.5m)v^2= 11200 u^2 so I have these two equations to work with: 28000 u = m v + 28000 v and 11200 u^2 = (...
Sunday, March 16, 2014 at 3:39pm

physics
A 28000 kg railroad freight car collides with a stationary caboose car. They couple together, and 20 percent of the initial kinetic energy is dissipated as heat, sound, vibrations, and so on. What is the mass of the caboose?
Sunday, March 16, 2014 at 3:19pm

Physics
no matter how i work it out, i keep getting the wrong answers. please help!!! i only have two more submissions before it closes on me. A sample of blood is placed in a centrifuge of radius 14.0 cm. The mass of a red blood cell is 3.0 x 10^-16 kg, and the magnitude of the force...
Sunday, March 16, 2014 at 3:18pm

physics
cool
Sunday, March 16, 2014 at 12:51pm

PHYSICS
Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 8.9-kg projectile from rest to a speed of 4.2 × 103 m/s. The net force accelerating the projectile is 1.4 × 105 N. ...
Sunday, March 16, 2014 at 12:38pm

Chemistry
The net reaction for fusion on a star like our Sun is: 4H(1,1) ==> He(4,2) + 2e(0,+1) Calculate the mass defect for this reaction. If one atom of He is formed this way, calculate the energy released. If one Kg of He is formed, calculate the energy released. The masses of ...
Sunday, March 16, 2014 at 12:07pm

physics
V = Vo + g*t = 0 + 9.8*3 = 29.4 m/s
Sunday, March 16, 2014 at 11:49am

Physics
A .75kg block is going at a velocity of 1.5m/s and moves on a frictionless surface. Then all of a sudden, the block hits a rough patch. The rough patch is .5m long and has a coefficient of friction of .25. Then it slides onto the frictionless surface again. The mass then ...
Sunday, March 16, 2014 at 11:34am

Physics - Current ????
There is no current specified so row straight across :)
Sunday, March 16, 2014 at 10:52am

Physics
A man wishes to cross a river from A to B, a distance of 800m. He can row at 8km per hour, in what direction should he head the boat to travel directly from A to B? How long does it take him to reach B? Please show working. Thank You!
Sunday, March 16, 2014 at 10:06am

physics
is the speed of the cannon ball relative to the car or the ground??
Sunday, March 16, 2014 at 7:06am

Physics
The acceleration of a particle moving only on a horizontal xy plane is given by a=5ti+6tj, where a is in meters per second-squared and t is in seconds. At t=0, the position vector r=(19.0m)i+(39.0m)j locates the particle, which then has the velocity vector v=(5.70m/s)i+(3.40m/...
Saturday, March 15, 2014 at 11:16pm

Physics ?
Why would I need a torque to move straight? why would I need any force to move at constant velocity? I am wondering who assigned this question.
Saturday, March 15, 2014 at 9:58pm

Physics
torque to move a block of m=200kg for 10m at an angle of 25 degree with a speed of 20m/s.
Saturday, March 15, 2014 at 9:20pm

Physics
well, you must have found the east and south speeds to get the angle from tan angle = speed south/speed east then Vf = sqrt (Vsouth^2 + Veast^2)
Saturday, March 15, 2014 at 7:44pm

Physics
A 49.5-kg skater is traveling due east at a speed of 2.88 m/s. A 72.5-kg skater is moving due south at a speed of 6.82 m/s. They collide and hold on to each other after the collision, managing to move off at an angle south of east, with a speed of vf. (a) Find the angle. (b) ...
Saturday, March 15, 2014 at 6:04pm

physics
A 12.0 g bullet is fired into a 13.9kg wooden block that is hanging straight down, suspended by a 2.00 m length of light line. The bullet has a muzzle velocity of 94.2 m/s. When the bullet hits the block, the bullet stays in the block. The block swings outward so that the line...
Saturday, March 15, 2014 at 6:01pm

Physics
The Achilles tendon is attached to the rear of the foot. Assume that a person has a mass of 53 kg and that D is twice as long as d. When a person elevates himself just barely off the floor on the "ball of one foot," estimate the tension in the Achilles tendon (...
Saturday, March 15, 2014 at 5:58pm

physics
(a) Suppose a hockey puck slides down a frictionless ramp with an acceleration of 5.60 m/s2. What angle does the ramp make with respect to the horizontal?
Saturday, March 15, 2014 at 5:14pm

Physics
Suppose the hand in holds a 20 kg mass . What force, FM, is required of the deltoid muscle? Assume the mass is 50 cm from the shoulder joint, the force of tension in the deltoid is directed 15° to the horizontal, and the mass of the arm alone is 3.8 kg.
Saturday, March 15, 2014 at 5:07pm

Physics
A block of mass 2.48 kg is kept at rest as it compresses a horizontal massless spring (k= 113 N/m) by 4.65 cm. As the block is released, it travels 0.462 m on a rough horizontal surface before stopping. The acceleration of gravity is 9.8 m/s^2. Calculate the coefficient of ...
Saturday, March 15, 2014 at 4:41pm

Physics
1. A 3 kg block collides with a massless spring of spring constant 90 N/m attached to a wall. The speed of the block was observed to be 1.5 m/s at the moment of collision. The acceleration of gravity is 9.8 m/s^2. How far does the spring compress if the surface on which the ...
Saturday, March 15, 2014 at 4:39pm

Physics
A racing car has a mass of 1530 kg. The acceleration of gravity is 9.8 m/s^2. What is its kinetic energy if it has a speed of 136 km/h? Answer in units of J.
Saturday, March 15, 2014 at 4:22pm

Physics
Shawn and his bike have a total mass of 58.5 kg. Shawn rides his bike 0.54 km in 17.2 min at a constant velocity. The acceleration of gravity is 9.8 m/s^2. What is Shawn’s kinetic energy? Answer in units of J.
Saturday, March 15, 2014 at 4:20pm

Physics
A team of dogs drags a 151 kg sled 0.863 km over a horizontal surface at a constant speed. The coefficient of friction between the sled and the snow is 0.223.The acceleration of gravity is 9.8 m/s^2. 1. Find the work done by the dogs. Answer in units of kJ. 2. Find the energy ...
Saturday, March 15, 2014 at 4:18pm

Physics
A cart loaded with bricks has a total mass of 22.3 kg and is pulled at constant speed by a rope. The rope is inclined at 27.3◦ degrees above the horizontal and the cart moves 9.3 m on a horizontal surface. The coefficient of kinetic friction between ground and cart is 0....
Saturday, March 15, 2014 at 4:15pm

Physics
A uniform ladder of mass m = 6.5 kg and length l = 2.1 m leans at an angle against a frictionless wall, Fig. 12-72. If the coefficient of static friction between the ladder and the ground is µs = 0.3, what is the minimum angle at which the ladder will not slip?
Saturday, March 15, 2014 at 3:51pm

physics
2;1
Saturday, March 15, 2014 at 12:39pm

Physics
A toy gun uses a spring to project a 6.1 g soft rubber sphere horizontally. The spring constant is 12.0 N/m, the barrel of the gun is 12.6 cm long, and a constant frictional force of 0.031 N exists between barrel and projectile. With what speed does the projectile leave the ...
Saturday, March 15, 2014 at 10:41am

Physics
A car of mass 1900kgs accelerates from rest to a speed of 27ms-1 in 8.1s.Calculate the average rate at which kinetic energy is supplied to the car during the acceleration.
Saturday, March 15, 2014 at 8:28am

physics
1) a bullet of mass 0.02 kg is fired into a block of wood of mass 1.5 kg resting on a horizontal table. The block moves offwith an initial speed of 8 m/s. Estimate the speed with the bullet strikes the block. 2) The bullet in question 1 is fired from a rifle of mass 2.5 kg. ...
Saturday, March 15, 2014 at 3:40am

physics
A ball of mass 0.1 kg is dropped from a height of 2 m onto a hard surface. If rebounds to a height of 1.5 m and it is in contact with the surface for 0.05s. Calculate the: (a) speed with which it strikes the surface. (b) speed with which it leaves the surface. (c) change in ...
Saturday, March 15, 2014 at 3:29am

physics
1)when a person stands on bathroom scales the scale reads 60 kg. Suppose the person stands on the same scales when in an elevator (lift). the elevator accelerates upwards at 2m/s2. Determine the new reading on the scale. 2)When a golfer strikes a golf ball it is in contact ...
Saturday, March 15, 2014 at 3:22am

physics
An object of weight 50 N is suspended vertically by two strings. The strings are of the same lenght and the angle between them is 60 degree. Draw a free body diagram of the forces acting on the object. Calculate the tension in the strings.
Saturday, March 15, 2014 at 3:13am

physics
A 3 kg mass attached to a string 6 m long is to be swung in a circular at a constant speed making one complete revolution in 1.25 s. Determine the value that the breaking strain that the string must not exceed if the string is not to break when the circular motion is in (a) a ...
Saturday, March 15, 2014 at 3:03am

Physics

Saturday, March 15, 2014 at 1:38am

Physics
b
Saturday, March 15, 2014 at 12:21am

physics
A missile of mass 1.20 102 kg is fired from a plane of mass 5.50 103 kg initially moving at a speed of 3.05 102 m/s. If the speed of the missile relative to the plane is 1.21 103 m/s, what is the final velocity of the plane?
Friday, March 14, 2014 at 9:45pm

physics
Two cars approach an ice-covered intersection. One car, of mass 1.26 103 kg, is initially traveling north at 10.6 m/s. The other car, of mass 1.66 103 kg, is initially traveling east at 10.6 m/s. The cars reach the intersection at the same instant, collide, and move off ...
Friday, March 14, 2014 at 9:44pm

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