Homework Help: Science: Physics

Recent Homework Questions About Physics

Physics
A person is standing outdoors in the shade where the temperature is 22 °C. (a) What is the radiant energy absorbed per second by his head when it is covered with hair? The surface area of the hair (assumed to be flat) is 180 cm2 and its emissivity is 0.84. (b) What would ...
Tuesday, April 30, 2013 at 8:33pm

Physics
The amount of heat per second conducted from the blood capillaries beneath the skin to the surface is 250 J/s. The energy is transferred a distance of 1.7 x 10-3 m through a body whose surface area is 1.8 m2. Assuming that the thermal conductivity is that of body fat, ...
Tuesday, April 30, 2013 at 7:59pm

Physics
What is the smallest possible value for the angular momentum L of an electron in the n=5 shell? Lmin= 0 kg*m^2/s What is the largest possible value for the angular momentum L of an electron in the n=5 shell? What is the Lmax? Please help I don't get this.Thank you!
Tuesday, April 30, 2013 at 6:58pm

Physics Need help plz
An 1900 kg car is traveling with a speed of (22 +- .22) m/s. With what maximum accuracy can its position be determined? delta x= in meters Can someone please help me out I am lost on this on...Thank you
Tuesday, April 30, 2013 at 4:58pm

physics
The figure shows a uniform beam of mass m pivoted at its lower end, with a horizontal spring attached between its top end and a vertical wall. The beam makes an angle è with the horizontal. (a) Find expression for the distance d the spring is stretched from equilibrium...
Tuesday, April 30, 2013 at 1:12pm

physics
what will the volume of a gas at 309K if its volume at 215K is 3.42 L? Assume the pressure is constant
Tuesday, April 30, 2013 at 11:14am

Physics
A ball of volume V=8 L is full of air with pressure higher than atmospheric pressure by Δp=2×10^4 Pa. The total mass of the ball and the air inside is 200 g. The ball is tossed up to a height h=20 m, then it falls down, collides with the ground, and bounces back up...
Tuesday, April 30, 2013 at 6:04am

physics
A ball of volume V=8 L is full of air with pressure higher than atmospheric pressure by Δp=2×10^4 Pa. The total mass of the ball and the air inside is 200 g. The ball is tossed up to a height h=20 m, then it falls down, collides with the ground, and bounces back up...
Tuesday, April 30, 2013 at 5:16am

Physics
Composite bar with end load (two segments) The composite bar BCD in the figure is composed of an inner aluminum cylindrical core of length 2L=2 m and radius R=1 cm and a sleeve of steel of length L=1 m and thickness R=1 cm surrounding the aluminum core in the CD section of the...
Tuesday, April 30, 2013 at 3:39am

Physics
Tapered bar with end load The small tapered bar BC has length L=0.1 m and is made of a homogeneous material with Young’s modulus E=10 GPa. The cross sectional area of the bar is slowly varying between A0=160 mm^2 (at B) and A0/2 (at C), as described by the function: A(x)=...
Tuesday, April 30, 2013 at 3:36am

Physics
Two runners have a race. The first runner decides to run with his full speed v₁=9 m/s over the 250 meters of the race and then slows to v₂=7 m/s for the rest, since he's tired. The second runner wants to save energy, so he runs with v₃=8 m/s for the whole...
Tuesday, April 30, 2013 at 1:33am

physics
A body of 150kg is located at a height of 45m. If allowed to fall freely to the ground. What will be its velocity on impact?
Monday, April 29, 2013 at 10:36pm

physics
How much heat, expressed in Kwh, is required to raise the temperature of water in a 20,000 gallon pool by 10 degrees C. ? This is a real world question, I'm 18 years old and I service my neighbors pool.
Monday, April 29, 2013 at 10:18pm

Physics- Coulomb's Law
1) Particles of charge Q1 = +77 µC, Q2 = +44 µC, and Q3 = -80 µC are placed in a line. The center one (Q2) is 0.35 m from each of the others. Calculate the net force on Q1 and Q2 due to the other charges. a) Force on Q1 Magnitude b) Force on Q2 Magnitude 2) A...
Monday, April 29, 2013 at 10:08pm

Physics
A 76.3-kN car is travelling at 68.7 mph when the driver decides to exit the freeway by going up a ramp. After coasting 355 m along the exit ramp the car\'s speed is 30.1 mph, and it is h = 14.3 m above the freeway. What is the magnitude of the average drag force exerted on...
Monday, April 29, 2013 at 9:25pm

physics
a cyclist moving with constant speed 10m/s develop a power of 400 watt. Calculate the average force exerting on the bicycle
Monday, April 29, 2013 at 8:38pm

physics
A car of 1500 kg mass moving with constant speed 10m/s for 10s . Calculate the average force acting on the car during this time
Monday, April 29, 2013 at 8:30pm

physics
900kgmassmovesat10m/s.whatisthebreakingforcerequiredtostopthecarin5seconds.
Monday, April 29, 2013 at 7:44pm

physics
40N50Nforcesactinginsamedirectionnetforceproducedis?
Monday, April 29, 2013 at 7:37pm

Physics
Your town is installing a fountain in the main square. If the water is to rise 14 m (45.9 feet) above the fountain, how much pressure must the water have as it moves slowly toward the nozzle that sprays it up into the air? Assume atmospheric pressure equal to 100,000 Pa.
Monday, April 29, 2013 at 7:35pm

physics
Three point charges lie in a straight line along the y-axis. A charge of q1 = -9.80 µC is at y = 6.00 m, and a charge of q2 = -8.20 µC is at y = -4.10 m. The net electric force on the third point charge is zero. Where is this charge located?
Monday, April 29, 2013 at 7:30pm

Physics
One of the concrete pillars that support a house is 2.1 m tall and has a radius of 0.35 m. The density of concrete is about 2.2 103 kg/m3. Find the weight of this pillar in pounds (1 N = 0.2248 lb).
Monday, April 29, 2013 at 7:24pm

physics
A man is 3/8th of the way across a railroad bridge when he hears a train coming. He knows that this passenger train cruises along at 60 MPH in this area. It turns out that he can run to either end of the bridge and jump off just ahead of the train. Assuming he runs a a ...
Monday, April 29, 2013 at 6:01pm

physics
a double slit located a distance x from a screen, with the distance from the center of the screen given by y. When the distance d between the slits is relatively large, there will be numerous bright spots, called fringes. It can be shown that, for small angles (where sin &#...
Monday, April 29, 2013 at 2:35pm

physics
In a running event, a sprinter does 4.9 105 J of work and her internal energy decreases by 9.1 105 J. (a) Determine the heat transferred between her body and surroundings during this event. J (b) What does the sign of your answer to part (a) indicate? There is no heat ...
Monday, April 29, 2013 at 11:23am

physics
A nuclear power plant has an electrical power output of 1900 MW and operates with an efficiency of 32%. If excess energy is carried away from the plant by a river with a flow rate of 1.0 106 kg/s, what is the rise in temperature of the flowing water? °C
Monday, April 29, 2013 at 11:22am

Physics
Consider a thin, infinitely long conducting ribbon that carries a uniform current density j(current per unit area). The width of the ribbon is w and its thickness s is extremely small (s<<w).P is a point in the plane of the ribbon, at a large distance (x>>s) from ...
Monday, April 29, 2013 at 11:21am

physics
Consider the following figure. (a) Determine the work done on a fluid that expands from i to f as indicated in the figure. J (b) How much work is done on the fluid if it is compressed from f to i along the same path? J
Monday, April 29, 2013 at 11:20am

physics
An ideal gas is enclosed in a cylinder with a movable piston on top of it. The piston has a mass of 8,000 g and an area of 5.00 cm2 and is free to slide up and down, keeping the pressure of the gas constant. (a) How much work is done on the gas as the temperature of 0.230 mol ...
Monday, April 29, 2013 at 11:13am

physics
A 100 g aluminum calorimeter contains 250 g of water. The two substances are in thermal equilibrium at 10°C. Two metallic blocks are placed in the water. One is a 50 g piece of copper at 84°C. The other sample has a mass of 58 g and is originally at a temperature of ...
Monday, April 29, 2013 at 11:09am

physics
A 79-kg sprinter accelerates from rest to a speed of 11.0 m/s in 4.8 s. (a) Calculate the mechanical work done by the sprinter during this time. J (b) Calculate the average power the sprinter must generate. W (c) If the sprinter converts food energy to mechanical energy with ...
Monday, April 29, 2013 at 11:08am

physics
A 22.0-L tank of carbon dioxide gas (CO2) is at a pressure of 9.40 105 Pa and temperature of 22.0°C. (a) Calculate the temperature of the gas in Kelvin. K (b) Use the ideal gas law to calculate the number of moles of gas in the tank. mol (c) Use the periodic table to ...
Monday, April 29, 2013 at 11:01am

physics
a stone of mass 50g is being rotated in a circle of radius 50cm with a uniform speed of 2m/s.what is thje accelerationof the stone?
Monday, April 29, 2013 at 8:19am

physics
a stone of mass 50g is being rotated in a circle of radius 50cm with a uniform speed of 2m/s.what is thje accelerationof the stone?
Monday, April 29, 2013 at 8:18am

Physics
A bullet is made up of what substance?
Monday, April 29, 2013 at 5:52am

Physics
A bullet is made up of what substance?
Monday, April 29, 2013 at 5:51am

Physics
A bullet is made up of what substance?
Monday, April 29, 2013 at 5:20am

physics
Tetherball is a game played by kids. The equipment consists of a volleyball on a string, with the other end of the string tied to the top of a post. Kids hit the ball back and forth around the post. Consider a volleyball of total mass 200 g attached to the top of a post by a 2...
Monday, April 29, 2013 at 4:53am

physics
A pair of fuzzy dice are hanging by a string in my car from the rear-view mirror. I hit the gas pedal, and while I accelerate the fuzzy dice no longer hang straight down, but instead make an angle θ of 15 degrees with respect to the vertical. How fast am I accelerating in...
Monday, April 29, 2013 at 4:52am

physics
Here's a neat trick. If your average ceramic bowl has a mass of 200 g, what is the difference in Newtons between the weight of the bowls on the top of her head before and after she does the trick? Details and assumptions The acceleration of gravity is −9.8 m/s2.
Monday, April 29, 2013 at 4:52am

physics
A freely running motor rests on a thick rubber pad to reduce vibration. The motor sinks h=10 cm into the pad. Estimate the rotational speed in RPM (revolutions per minute) at which the motor will exhibit the largest vertical vibration.
Monday, April 29, 2013 at 4:38am

physics
a wheel radius 0.25 m is mounted on a frictionless horizontal axle. the moment of inertia of the wheel about the axis is 0.040. a light cord wrapped around the wheel supports the 0.50 kg of box. the wheel is released from the rest. what is the magnitude of acceleration of the ...
Sunday, April 28, 2013 at 10:22pm

physics
A ball hands on a string in the bus from the rear-view mirror. Once the driver hits the gas pedal, and while he accelerates, the ball no longer hangs straight down, but instead make an angle è of 15 degrees with respect to the vertical. How fast is the bus driver ...
Sunday, April 28, 2013 at 8:48pm

Physics
An trapdoor is 0.91 m square, has a mass of 11 kg, and is hinged along one side with a latch on the opposite side. If the center of mass is located 0.1 m toward the hinged side from the center, what are the magnitudes of the forces on the latch and the hinge from the door?
Sunday, April 28, 2013 at 7:35pm

Physics
To combat wasteful habits, we often speak of “conserving energy,” by which we mean turning off lights, heating or cooling systems, and hot water when not being used. In this chapter, we also speak of “energy conservation.” Distinguish between these two ...
Sunday, April 28, 2013 at 6:55pm

Physics
When you jump upward, your hang time is the time your feet are off the ground. Does hang time depend on your vertical component of velocity when you jump, your horizontal component of velocity, or both? Defend your answer. Please help!!! Thank you in advance...
Sunday, April 28, 2013 at 6:53pm

Physics Electricity and magnetism
A current with sinusoidal time-dependence, whose peak value is 3.55 A and frequency is 463 cycles per second, passes through a long straight wire. A rectangular 72.2 cm × 32.5 cm loop of copper wire is located 80.2 cm from the wire and is coplanar with it. Calculate the ...
Sunday, April 28, 2013 at 5:45pm

physics
In order for me to fill the table of equilibrium, how do I calculate change(mol) Please give me in detail about filling the table
Sunday, April 28, 2013 at 4:26pm

physics
Construct a 5th mode standing wave on a string that has an unknown mass hanging from one end. The distance between fixed ends of the string is 0.9 meters. If the wave speed on the 1.3 meter string is 216 meters per seconds and the string has a mass of 3 grams, what is the ...
Sunday, April 28, 2013 at 4:22pm

Physics
You need to produce a solenoid that has an inductance of 2.51 μH . You construct the solenoid by uniformly winding 1.17 m of thin wire around a tube. How long, in centimeters, should the tube be?
Sunday, April 28, 2013 at 4:14pm

Physics
Calculate d energy of d 3rd level of an atom if d ground state energy is -24.8ev
Sunday, April 28, 2013 at 2:32pm

Physics
Wat is d bond between silicon and germanium
Sunday, April 28, 2013 at 2:28pm

Physics
The boom weighs 2450 and is attached to a friction less pivot at its lower end. It is not uniform; the distance of its center of gravity from the pivot is 39.0% of its length. What is the tension in the guy wire? Link to picture of problem which is needed to solve the problem...
Sunday, April 28, 2013 at 1:58pm

physics
a bullet of mass 0.015kg strikes a ballistic pendullum of mass 2kg.the centre of mass of the pendulum rises a verticle distance of 0.12m.assuming that the bullet remains embedded in the pendulum, calculate the bullets initial speed.(show all calculations and steps)
Sunday, April 28, 2013 at 1:57pm

Physics
52*10E-10Kg
Sunday, April 28, 2013 at 12:08pm

Engineering
A physics major is working to pay his college tuition by performing in a traveling carnival. He rides a motorcycle inside a hollow transparent plastic sphere. After gaining sufficient speed, he travels in a vertical circle with a radius of 13.4 . The physics major has a mass ...
Sunday, April 28, 2013 at 11:16am

physics
Consider two straight bars of uniform cross section made of the same material. Bar 1 has an axial length of and a square cross section with side length . Bar 2 has an axial length of and a round cross section with diameter. When subjected to axial tension, bar 1 elongates by...
Sunday, April 28, 2013 at 11:14am

physics
a rocket is fire vertically and ascends with constant vertical axceleration of 20 m/s^2 for 1min. its fuel is then all used and it continues to move as a free falling bodyn neglexting rhe variation of g altitude, compute a) the max altitude reached by the rocket and b) the ...
Sunday, April 28, 2013 at 10:40am

Physics
A 39.0 kg box initially at rest is pushed 4.50 m along a rough, horizontal floor with a constant applied horizontal force of 135 N. If the coefficient of friction between box and floor is 0.300, find the following. (a) the work done by the applied force J (b) the increase in ...
Sunday, April 28, 2013 at 8:23am

physics
Two identical wires with resistance,R and mass,m rest on two smooth parallel superconducting (zero resistance) rails. Initially, they are separated by a distance,D=70 cm. Suddenly, a uniform magnetic field B, perpendicular to the plane of the rails is switched on and the wires...
Sunday, April 28, 2013 at 4:38am

PHYSICS!!!! help!!!
A perfectly spherical, but squishable ball of radius 10 cm is blown up to an internal pressure of 2 atm. The ball is placed between two perfectly vertical walls and the walls are slowly squeezed together. Initially the ball slips down the walls, but when the walls are 18 cm ...
Sunday, April 28, 2013 at 4:35am

physics
two people carry a heavy electric motor by placing it on a light board 2m long.one person lifts at one end with a force of 700N, and the other lifts the opposite end with a force of 400N.Calculate the weight of the motor and determine where its center of Gravity is Located
Sunday, April 28, 2013 at 4:14am

physics
three point charges each of magnitude +q are located at the vertices of an equilateral triangle of side L. what magnitude of charge should be placed at the centroid of triangle to keep all the three charges in equilibrium?
Sunday, April 28, 2013 at 3:15am

Physics
A park ranger wants to shoot a monkey hanging from a branch of a tree with a tranquilizing dart. The ranger aims directly at the monkey, not realizing that the dart will follow a parabolic path and thus will fall below the monkey. The monkey, however, sees the dart leave the ...
Sunday, April 28, 2013 at 12:54am

College Physics
A uniform meter stick of mass M has an empty paint can of mass m hanging from one end. The meter stick and the can balance at a point 19.9 cm from the end of the stick where the can is attached. When the balanced stick-can system is suspended from a scale, the reading on the ...
Saturday, April 27, 2013 at 10:55pm

Physics
The boom weighs 2450 and is attached to a friction less pivot at its lower end. It is not uniform; the distance of its center of gravity from the pivot is 39.0 of its length. What is the tension in the guy wire? Link to picture of problem which is needed to solve the problem...
Saturday, April 27, 2013 at 10:14pm

physics 102
An aluminum wing on a plane is 30.6 m long when the temperature is 20 oC. At what temperature would the wing be 0.06 m shorter
Saturday, April 27, 2013 at 8:42pm

Physics
Consider a thin, infinitely long conducting ribbon that carries a uniform current density j (current per unit area). The width of the ribbon is w and its thickness s is extremely small (s≪w). P is a point in the plane of the ribbon, at a large distance (x≫s) from ...
Saturday, April 27, 2013 at 4:42pm

Physics
A current I=2.3 A flows around a continuous path that consists of portions of two concentric circles of radii a and a/2, respectively, where a=6 cm, and two straight radial segments. The point P is at the common center of the two circle segments. Calculate the components Bz of...
Saturday, April 27, 2013 at 4:41pm

Physics
The boom weighs 2450 and is attached to a friction less pivot at its lower end. It is not uniform; the distance of its center of gravity from the pivot is 39.0 of its length. Picture Link: tinypic./view.php?pic=53qp3m&s=5 What is the tension in the guy wire?
Saturday, April 27, 2013 at 4:41pm

Physics
A charged particle with mass m, charge |q|=6.4 ×10−19C and speed v=3 ×106 m/s enters from the bottom of the figure and traces out the trajectory shown in the fields shown. The only electric field E=5 ×103 V/m is in the region where the trajectory of the...
Saturday, April 27, 2013 at 4:38pm

Physics
A spherical shell of radius R carries a uniform surface charge density (charge per unit area) σ. The center of the sphere is at the origin and the shell rotates with angular velocity ω (in rad/sec) around the z-axis (z=0 at the origin) (a) Calculate the magnitude of ...
Saturday, April 27, 2013 at 4:36pm

Physics
A body is moving north at 12m/s and 5 seconds later it has a velocity of 30m/s in the same direction. What was the acceleration of the body?
Saturday, April 27, 2013 at 4:06pm

Physics
A Body with a mass of 150kg is located at a height of 45 m. If allowed to fell freely to the ground. What will be its velocity on impact? KE= 1/2*m*v^2 PE= m*g*h 1/2*m*v^2= m*g*h 1/2*150kg*45m*v^2= 150kg*9.81*45m 3375* v^2= 66217.5 3375*v^2/3375= 66217.5/3375 v^2= 19.62m/s Is ...
Saturday, April 27, 2013 at 3:45pm

physics
To combat wasteful habits, we often speak of “conserving energy,” by which we mean turning off lights, heating or cooling systems, and hot water when not being used. In this chapter, we also speak of “energy conservation.” Distinguish between these two usages.
Saturday, April 27, 2013 at 3:24pm

physics
Why bother using a machine if it cannot multiply work input to achieve greater work output?
Saturday, April 27, 2013 at 3:22pm

physics
When a cannon with a longer barrel is fired, the force of expanding gases acts on the cannonball for a longer distance. What effect does this have on the velocity of the emerging cannonball? (Do you see why long-range cannons have such long barrels?)
Saturday, April 27, 2013 at 3:21pm

Physics
In grandpa’s time automobiles were previously manufactured to be as rigid as possible, whereas autos are now designed to crumple upon impact. Why?
Saturday, April 27, 2013 at 3:20pm

physics
A spherical shell of radius carries a uniform surface charge density (charge per unit area) . The center of the sphere is at the origin and the shell rotates with angular velocity (in rad/sec) around the -axis ( at the origin). Seen from below, the sphere rotates clockwise. (...
Saturday, April 27, 2013 at 3:11pm

Physics
A body with a mass of 75 kg is located at a height of 20 m. If it is allowed to free fall to the ground. What will be its velocity on impact?
Saturday, April 27, 2013 at 2:52pm

physics
What type of contamination involves Rags, tie wraps, and safety wire?
Saturday, April 27, 2013 at 12:26pm

physics
A Martian rover is moving up a hill sloped at 30.0° with the horizontal. If it has a constant velocity of 1.50 meters/second, calculate its vertical displacement after 21.0 seconds.
Saturday, April 27, 2013 at 12:08pm

physics
Two masses are slideing on a horizon frictionless surface. A 10 kg mass has a velocity of 9 m/s in the x direction and a 20 kg mass has a velocity of 12 m/s in the y direction .the masses collide and stick together, what is he final velocity of the composite mass? Draw and ...
Saturday, April 27, 2013 at 11:05am

physics
With a mass = 10 k .. the horizontal surface on which the block slides is frictionless. The speed of the block before it touches the spring is 6.0 m/s. How fast is he block moving at the instant the spring has been compressed 15 cm? K=2.0kN/m
Saturday, April 27, 2013 at 10:59am

physics
A 2.0 mass tied to the end of a 1.5m string swings as a pendulum. At the lowest point In its swing, the speed of the mass is 4.6 m/s. What is speed of the mass when at the instant when the string makes and angle of 35 degrees with the vertical?
Saturday, April 27, 2013 at 10:53am

Physics
Help please, Four charges are placed at the four corners of a square of side 15 cm.The charges on the upper left and right corners are +3 uC and -6 uC respectively. The charges on the lower left and right corners are -2.4uC and-9 uC respectively. The net force on -6uC charge ...
Saturday, April 27, 2013 at 10:25am

Physics
Inside an insulated container, a 250-g ice cube at 0°C is added to 200 g of water at 18°C. (i) What is the final temperature of the system? (ii) What is the remaining ice mass?
Saturday, April 27, 2013 at 10:05am

physics
I post this early ; but didnt understand the answer.. a 3-kg object falls from a height of 10m to the ground. The work done by air resistance ia 20 J. What is the kinetic energy of the object as it hits the ground..
Saturday, April 27, 2013 at 9:27am

Physics
A pair of in-phase stereo speakers is placed side by side, 0.85 m apart. You stand directly in front of one of the speakers, 1.1 m from the speaker. What is the lowest frequency that will produce constructive interference at your location?
Saturday, April 27, 2013 at 9:25am

physics
Give the potential energy function U = 2×^2-25×: determine the force function for this potential.
Saturday, April 27, 2013 at 8:31am

physics
Give the potential energy function U = 2×^2-25×: determine the force function for this potential.
Saturday, April 27, 2013 at 8:29am

physics
A 3 kg objects falls from a height of 10 m to the ground. the work done by air resistance is 20 J. What is the kinetic energy of the object as it hits the ground?
Saturday, April 27, 2013 at 8:21am

physics
Consider a five-pointed star made of resistors as shown below. Each resistor has resistance R=6 Ω. Find the equivalent resistance in Ohms between the points A and B.
Saturday, April 27, 2013 at 7:26am

physics
Climbing to the top of Mount Everest is hard. But, it's slightly easier than you might think as people weigh less as they climb to the top. Let WE be a person's weight on top of Mount Everest and WS be their weight at sea level. What is the value of 1−WE/WS?
Saturday, April 27, 2013 at 7:16am

physics
two charge 5NC and -2NC are placed at a point (5cm,0,0)and (23cm,0,0)in a region of a space where there is no other electric field.calculate the electrostatic potential energy of this charged system
Saturday, April 27, 2013 at 3:25am

PHYSICS
3. A particle of mass m= 5.00 kg is released from point A(at rest) and slides on the frictionless track shown in Figure below. Determine: ( 8 marks ) a. the particleâ€™s speed at points B and C and (4marks) b. the net work done by the gravitational force in ...
Saturday, April 27, 2013 at 2:57am

physics
2. At time t =0, the current to the dc motor is reversed, resulting in an angular displacement of the motor shaft given by θ = (198 rad/s)t – (24 rad/s2)t2 – (2 rad/s3)t3 a. At what time is the angular velocity of the motor shaft zero? b. Calculate the angular ...
Saturday, April 27, 2013 at 1:06am

Physics
Two large, parallel, conducting plates are 20 cm apart and have charges of equal magnitude and opposite sign on their facing surfaces. An electrostatic force of 3.0 10-15 N acts on an electron placed anywhere between the two plates. (Neglect fringing.) a) Find the magnitude of...
Saturday, April 27, 2013 at 12:32am

Physics
A spring oriented vertically is attached to a hard horizontal surface as in the figure below. The spring has a force constant of 1.64 kN/m. How much is the spring compressed when a object of mass m = 2.35 kg is placed on top of the spring and the system is at rest?
Friday, April 26, 2013 at 9:23pm

math/physics
Estimate the percentage savings in the fuel bill if the thermostat is set back from 68 degrees F to 50 degrees F for 12 hours of the day, and left at 68 degrees F for the other 12 hours, assuming an outside temperature of 15 degrees F all day.
Friday, April 26, 2013 at 6:48pm

physics
a 100-kg b
Friday, April 26, 2013 at 6:18pm

Physics
11. An object with a charge of +6.0 µC is 0.30 m from a second object and experiences an attractive force of 1.80 N. What is the magnitude of the charge on the second object? (µC = 1.0 × 10-6 C) (Answer: -3.0 µC) Can someone please explain how to do ...
Friday, April 26, 2013 at 4:44pm

Physics
Two identical positive charges exert a repulsive force of 7.0 10-9 N when separated by a distance of 3.2 10-10 m. Calculate the charge of each. _C
Friday, April 26, 2013 at 4:13pm

physics
A block of mass 8.50 is sliding along a smooth surface when it encounters a 0.800 long region of roughness with =0.310. The block emerges from the rough patch at a reduced speed of 5.00 and continues on.
Friday, April 26, 2013 at 3:09pm

Physics
How much heat, expressed in Kwh, is required to raise the temperature of water in a 20,000 gallon pool by 10 degrees C. ?
Friday, April 26, 2013 at 2:45pm

Physics
A spherical shell of radius R carries a uniform surface charge density (charge per unit area) σ. The center of the sphere is at the origin and the shell rotates with angular velocity ω (in rad/sec) around the z-axis (z=0 at the origin). Seen from below, the sphere ...
Friday, April 26, 2013 at 1:20pm

Physics
A current I=2.3 A flows around a continuous path that consists of portions of two concentric circles of radii a and a/2, respectively, where a=5 cm, and two straight radial segments. The point P is at the common center of the two circle segments. Calculate the components of ...
Friday, April 26, 2013 at 1:19pm

Physics
The switch in the circuit below has been open for a long, long time, R1=8.0 Ohm, R2=5.0 Ohm, L=0.03 H, V=1 V. The internal resistance of the battery is negligibly small. Determine the currents I1,I2,I3 (in Ampere) in the resistors and in the self-inductor at the moment (a) ...
Friday, April 26, 2013 at 1:19pm

Physics
Two voltmeters, Vright and Vleft, each with an internal resistance of 106 Ω are connected through wires of negligible resistance (see the circuit below). The “+" side of both voltmeters is up as shown. A changing magnetic field is present in the shaded area. At ...
Friday, April 26, 2013 at 1:18pm

Physics-- please help me finish!!
Ive tried using the formulas my teacher gave me, however I can't seem to get the right answers. Please help! A 1.4-kg block hangs from a spring. A 363-g body hung below the block stretches the spring 2.6 cm farther. What is the spring constant? When the 363-g body is ...
Friday, April 26, 2013 at 1:06pm

physics
What is the angular momentum (in kilogram-meter^2/second) of a 500.0 g ball rotating on the end of a string in a circle of radius 1.45 m at an angular speed of 1.50 rad/s?
Friday, April 26, 2013 at 12:17pm

physics
A 2.70 m long pole is balanced vertically on its tip. What will be the speed (in meters/second) of the tip of the pole just before it hits the ground? (Assume the lower end of the pole does not slip.)
Friday, April 26, 2013 at 12:04pm

physics for physical science
(a)what is the magnitude of the gravitational force of the earth on a surveillance satellite of mass 1040kg that is in a grazing circular orbit 100 km above the surface of the earth. (b)find the magnitude of the acceleration of the satellite in such a grazing orbit. (c)...
Friday, April 26, 2013 at 11:27am

physics
Consider a thin, infinitely long conducting ribbon that carries a uniform current density j (current per unit area). The width of the ribbon is w and its thickness s is extremely small (s≪w). P is a point in the plane of the ribbon, at a large distance (x≫s) from ...
Friday, April 26, 2013 at 11:20am

physics
A current I=2.3 A flows around a continuous path that consists of portions of two concentric circles of radii a and a/2, respectively, where a=6 cm, and two straight radial segments. The point P is at the common center of the two circle segments. Calculate the components of ...
Friday, April 26, 2013 at 11:19am

physics
A Bainbridge mass spectrometer is shown in the figure. A charged particle with mass m, charge |q|=3.2 ×10−19C and speed v=3 ×10@6 m/s enters from the bottom of the figure and traces out the trajectory shown in the fields shown. The only electric field E=11 &...
Friday, April 26, 2013 at 11:18am

physics
Two voltmeters, Vright and Vleft, each with an internal resistance of 106 Ω are connected through wires of negligible resistance (see the circuit below). The “+" side of both voltmeters is up as shown. A changing magnetic field is present in the shaded area. At ...
Friday, April 26, 2013 at 11:14am

physics for physical science
a bullet of mass 0.015kg strikes ballistic pendulum of mass 2.0kg .the center of mass of the pendulum rises a vertical distance of 0.12m.assuming that the bullet remains embedded in the pendulum, calculate the bullet's initial speed.
Friday, April 26, 2013 at 10:56am

physics
what pressure (in atm) would be exerted by 76g of fluorine gas in a 1.5 litre vessel at -37 degrees Celsius?
Friday, April 26, 2013 at 10:46am

Physics
A 10 m platform diver during his diving can increase his rotation rate from an initial rate of 0.8 rev/s to a maximum of 3.3 rev/s. If his initial moment of inertia was 10 kg·m2, what is his moment of inertia at his maximum rotation rate?
Friday, April 26, 2013 at 10:44am

Physics
A spherical shell of radius R carries a uniform surface charge density (charge per unit area) \sigma. The center of the sphere is at the origin and the shell rotates with angular velocity \omega (in rad/sec) around the z-axis (z=0 at the origin). Seen from below, the sphere ...
Friday, April 26, 2013 at 8:37am

physics
Details and assumptions Note: Points ABCDE are labeled for easy reference if you need to use some combination of them in a solution. Request clarification or dispute Print this
Friday, April 26, 2013 at 3:13am

physics
A large storage tank, open to the atmosphere at the top and ﬁlled with water, develops a small hole in its side at a point 18 m below the water level. The rate of ﬂow of water from the leak is 1.6 × 10−3 m3 /min. Determine the speed at which the water...
Friday, April 26, 2013 at 12:47am

physics
Three moles of nitrogen gas, N2, at 26.8 ◦C are contained in a 35.8 L cylinder. Find the pressure the gas exerts on the cylinder walls. Answer in units of Pa
Friday, April 26, 2013 at 12:35am

physics
Four charges are placed at the four corners of a square of side 15 cm.The charges on the upper left and right corners are +3 uC and -6 uC respectively. The charges on the lower left and right corners are -2.4uC and-9 uC respectively. The net force on -6uC charge is ?
Thursday, April 25, 2013 at 11:24pm

Physics
An object of mass 20kg slides down an inclined plane at an angle of 30 degree to the horizontal. The coefficient of static friction is?
Thursday, April 25, 2013 at 11:20pm

College Physics
A speck of charged dust with a mass of 39mu g. is kept levitating by putting it in an electric field. If you must apply a field of 10 N/C to keep it suspended in mid-air, what is the charge on the speck of dust? Can someone please help soon? I got this wrong on my last test ...
Thursday, April 25, 2013 at 9:55pm

physics
two charges originally separated by 10cm are moved further apart untill the force between them has decreased by a factor of 10. How far apart are these charges?
Thursday, April 25, 2013 at 8:19pm

physics
At the instant a race began, a 74.0 kg sprinter exerted a force of 850 N on the starting block at a 23.0 degree angle with respect to the ground. what was the horizontal acceleration of the sprinter?
Thursday, April 25, 2013 at 7:41pm

physics
What is the angular momentum (in kilogram-meter^2/second) of a 500.0 g ball rotating on the end of a string in a circle of radius 1.54 m at an angular speed of 2.50 rad/s?
Thursday, April 25, 2013 at 7:24pm

Physics
A 1.10 N bird descends onto a branch that bends and goes into SHM with a period of 0.60 s. Determine the effective elastic force constant of the branch.
Thursday, April 25, 2013 at 6:03pm

Physics
A massless spring with spring constant 17.1 N/m hangs vertically. A body of mass 0.210 kg is attached to its free end and then released. Assume that the spring was unstretched before the body was released. What is the amplitude of the resulting motion?
Thursday, April 25, 2013 at 6:02pm

Physics
A massless spring with spring constant 17.1 N/m hangs vertically. A body of mass 0.210 kg is attached to its free end and then released. Assume that the spring was unstretched before the body was released. How far below the initial position does the body descend?
Thursday, April 25, 2013 at 6:01pm

Physics
what force can cause the displacement of an object but does no work??
Thursday, April 25, 2013 at 4:58pm

College Physics
The rectangular coils in a 201-turn generator are 14 cm by 17 cm. What is the maximum emf produced by this generator when it rotates with an angular speed of 525 rpm in a magnetic field of 0.81 T? I'm not sure what equations to use.
Thursday, April 25, 2013 at 4:39pm

physics
In one of Michelson's experiments, a beam from a revolving mirror traveled 12 km to a stationary mirror. How long a time interval elapsed before the beam returned to the mirror?
Thursday, April 25, 2013 at 4:33pm

Physics
Why do the passengers in high-altitude jet planes feel the sensation of weight while passengers in the International Space Station do not? Please help; need an original answer no Google search. Thank you in advance...
Thursday, April 25, 2013 at 3:58pm

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