Friday
May 24, 2013

# Homework Help: Science: Physics

PHysics
The sound emitted by bats has a wavelength of 3.45 mm. What is the frequency in air? The speed of sound in air is 343 m/s.
Thursday, March 21, 2013 at 7:25pm

physics
In Example 5.8, we investigated the apparent weight of a fish in an elevator. Now consider a 72.0 kg man standing on a spring scale in an elevator. Starting from rest, the elevator ascends, attaining its maximum speed of 1.20 m/s in 0.80 s. It travels with this constant speed ...
Thursday, March 21, 2013 at 6:14pm

Physics
A 4.10 m long, 590 kg steel beam extends horizontally from the point where it has been bolted to the framework of a new building under construction. A 66.0 kg construction worker stands at the far end of the beam. What is the magnitude of the torque about the point where the ...
Thursday, March 21, 2013 at 5:56pm

Physics
If a proton is moving in a magnetic field with a speed of 4 × 106m/s and is executing uniform circular motion with a radius of 10 cm, what is the magnetic field?
Thursday, March 21, 2013 at 5:46pm

Physics help
A 90 kg parachutist in free fall has an acceleration of 6.8 m/s^2. What is the frictional force provided by air resistance when she is accelerating at this rate? For this question i got 612N but the text book answer says it is 270N. Pls help!! I'm confused
Thursday, March 21, 2013 at 5:46pm

Physics
A dock worker loading crates on a ship ﬁnds that a 18 kg crate, initially at rest on a horizontal surface, requires a 71 N horizontal force to set it in motion. However, after the crate is in motion, a horizontal force of 46 N is required to keep it moving with a ...
Thursday, March 21, 2013 at 5:44pm

physics
A railroad car with a mass of 2000kg is rolling at a speed of 15m/s. What force would be required to stop the car in 10 seconds?
Thursday, March 21, 2013 at 5:29pm

PHYSICS
Determining how the charges distribute on the surface of a conductor is, in general, a very difficult problem. We know that if we charge a conductor the charges go to the surface and redistribute so that the electric field in the conductor vanishes. One of the few shapes for ...
Thursday, March 21, 2013 at 5:16pm

PHYSICS
A 10 g bullet is fired horizontally into a 1 kg block of wood hanging from a 1 m long string attached to the ceiling, getting stuck in the block. Due to the impact, the block then swings on the string to a maximum angle of 60 degrees with respect to the vertical. How fast was ...
Thursday, March 21, 2013 at 5:15pm

PHYSICS
A rectangular conducting homogeneous (which means the material is the same throughout) block has dimensions 1cm×2cm×3cm . A voltage V is applied between all opposite faces of the block and the corresponding currents were recorded. What is the maximum current ...
Thursday, March 21, 2013 at 5:14pm

physics
A small 0.482-kg object moves on a frictionless horizontal table in a circular path of radius 0.77 m. The angular speed is 6.18 rad/s. The object is attached to a string of negligible mass that passes through a small hole in the table at the center of the circle. Someone under...
Thursday, March 21, 2013 at 4:45pm

Physics
A man drags a 71.5-kg crate across the floor at a constant velocity by pulling on a strap attached to the bottom of the crate. The crate is tilted 24.5° above the horizontal, and the strap is inclined 63.0° above the horizontal. The center of gravity of the crate ...
Thursday, March 21, 2013 at 4:36pm

physics
A man drags a 71.5-kg crate across the floor at a constant velocity by pulling on a strap attached to the bottom of the crate. The crate is tilted 24.5° above the horizontal, and the strap is inclined 63.0° above the horizontal. The center of gravity of the crate ...
Thursday, March 21, 2013 at 4:24pm

Physics
An electron with a velocity of v = (3 x + 4 y + 2 z) × 106m/s enters a region where there is both a magnetic field and an electric field. The magnetic field is B = (1 x - 2 y + 4 z)T. If the electron experiences no force as it moves, calculate the electric field.
Thursday, March 21, 2013 at 4:17pm

Physics
A charged particle is moving downward with an initial speed of 5 × 106m/s when it encounters a uniform magnetic field that points east to west. (a) If the initial force on the particle is to the north, is the particle positive or negative? (b) If B = .25 T and the ...
Thursday, March 21, 2013 at 4:17pm

Physics
An electron with a velocity of v = (3 x + 4 y + 2 z) × 106m/s enters a region where there is both a magnetic field and an electric field. The magnetic field is B = (1 x - 2 y + 4 z)T. If the electron experiences no force as it moves, calculate the electric field.
Thursday, March 21, 2013 at 4:16pm

Physics
An electron is shot into a uniform magnetic field B = (.5 x + .8 y)T with an initial velocity of v = (4 x + 3 y) × 106m/s. What is the force on the electron?
Thursday, March 21, 2013 at 4:00pm

Physics
A series circuit contains only a resistor and an inductor. The voltage V of the generator is fixed. If R = 10 Ω and L = 4.2 mH, find the frequency at which the current is one-half its value at zero frequency? Answer in Hz
Thursday, March 21, 2013 at 3:16pm

Physics
In the absence of a nearby metal object, the two inductances (LA and LB) in a heterodyne metal detector are the same, and the resonant frequencies of the two oscillator circuits have the same value of 510.0 kHz. When the search coil (inductor B) is brought near a buried metal ...
Thursday, March 21, 2013 at 3:09pm

Physics
A series RCL circuit has a resonant frequency of 1530 Hz. When operating at a frequency other than 1530 Hz, the circuit has a capacitive reactance of 5.0 Ω and an inductive reactance of 33.0 Ω. What is the value of L? (Answer in H) What it the value of C? (Answer in F)
Thursday, March 21, 2013 at 3:08pm

Physics
6. If your boat weighs 1200 N, how much water will it displace when it’s floating motionless at the surface of the lake?
Thursday, March 21, 2013 at 2:26pm

physics
vector R= (t^3-9t^2 + 24t + 10)jhat
Thursday, March 21, 2013 at 2:10pm

Quantum Physics
In this problem, we will carry out some steps of the quantum factoring algorithm for N = 15 (a) What is the period k of the periodic superposition set up by the quantum factoring algorithm if it chooses x = 2 ? (b) Assume that we found this k using period finding algorithm. ...
Thursday, March 21, 2013 at 1:31pm

Physics
A half-atwood machine is constructed, as shown in the drawing below. The table is NOT frictionless, M1 is 50 grams, and M2 is 30 grams. Mass M2 descends 32 cm in 18 seconds. Find the tension in the wire.
Thursday, March 21, 2013 at 1:17pm

physics
The launching mechanism of a toy gun consists of a spring of unknown spring constant, as shown in the figure below. If the spring is compressed a distance of 0.160 m and the gun fired vertically as shown, the gun can launch a 21.0-g projectile from rest to a maximum height of ...
Thursday, March 21, 2013 at 12:43pm

physics
a student plucks a guitar string and the vibrations produce a sound wave with a freuency of 650 hertz. Calculate the wavelength of the sound wave in air at STP.
Thursday, March 21, 2013 at 12:42pm

physics
Object I is a solid cylinder with diameter d has resistance R. What would be resistance of another object made of the same material and with the same mass as Object I but has the cross section shown below (it is a hollow cylinder with outer diameter 2d and inner diameter d). R...
Thursday, March 21, 2013 at 10:17am

physics
Object I is a solid cylinder with diameter d has resistance R. What would be resistance of another object made of the same material and with the same mass as Object I but has the cross section shown below (it is a hollow cylinder with outer diameter 2d and inner diameter d).
Thursday, March 21, 2013 at 10:10am

Physics
A conical pendulum is formed by attaching a 0.60kg ball to a 1.0m -long string, then allowing the mass to move in a horizontal circle of radius 30cm. 1. What is the tension in the string 2. What is the ball's angular velocity in rpm?
Thursday, March 21, 2013 at 9:05am

physics
a picture frame 25 kg hung over a nail by a string attatched to two hookes in the upper bar . find tension using parallelogram law
Thursday, March 21, 2013 at 8:01am

physics
The sun goes around the center of our galaxy once every 250 million years. The sun is also 2.55×10^20 m from the center of our galaxy. What is the acceleration of our sun towards the center of the galaxy in m/s^2?
Thursday, March 21, 2013 at 6:41am

physics
pv = constant to find the work done
Thursday, March 21, 2013 at 6:06am

physics impulse
A 2 kg cart rolls across the floor and runs into the wall and sticks. Before the collision the cart has a velocity of 4 m/s in the x direction. The collision took place in 0.1 s. 1) What was the cart's momentum before the collision? 2) What was the cart's KE before the...
Thursday, March 21, 2013 at 5:55am

physics
a 2.1 weight receives 210 j of kinetic energy by a launcher, which is pointed straight up.
Thursday, March 21, 2013 at 1:58am

physics
a 2.1 weight receives 210 j of kinetic energy by a launcher, which is pointed straight up.
Thursday, March 21, 2013 at 1:57am

physics
a40w motor conectedto a 9v battery can lift an object 40m in 10s
Thursday, March 21, 2013 at 12:38am

Physics
If a vehicle starts at 31 km/h and only travels 4.7m in 1.1 seconds due to deceleration, how fast is it going after 1.1 seconds?
Wednesday, March 20, 2013 at 11:07pm

physics
Two charges, qA and qB, are separated by a distance, d, and exert a force, F, on each other. Analyze Coulomb's law and answer the following questions. (a) What new force will exist if qA is doubled? (b) What new force will exist if qA and qB are cut in half? (c) What new ...
Wednesday, March 20, 2013 at 10:47pm

physics
A strong lightning bolt transfers about 26 C to Earth. How many electrons are transferred?
Wednesday, March 20, 2013 at 10:24pm

HELP PHYSICS!
Four charges with equal magnitudes of 7.81 × 10-12 C are placed at the corners of a rectangle. The lengths of the sides of the rectangles are 2.52 cm and 4.02 cm. Find the magnitude of the electric field at the center of the rectangle in Figures a and b. img166....
Wednesday, March 20, 2013 at 9:31pm

PHYSICS HELP!
The drawing shows a square, each side of which has a length of L = 0.25 m. Two different positive charges q1 and q2 are fixed at the corners of the square. Find the electric potential energy of a third charge q3 = -5 x 10-9 C placed at corner A and then at corner B. q1= 1.5e-9...
Wednesday, March 20, 2013 at 9:31pm

Physics
A certain car is capable only of accelerat ing at 3.0m/s 2 , braking (decelerating) at 5.0m/s 2 , and moving at constant velocity. The car is init ially located 100m from a road sign. The driver, starting from rest, begins to accelerat e towards the sign. After maintaining ...
Wednesday, March 20, 2013 at 7:54pm

Physics
Four charges with equal magnitudes of 7.81 × 10-12 C are placed at the corners of a rectangle. The lengths of the sides of the rectangles are 2.52 cm and 4.02 cm. Find the magnitude of the electric field at the center of the rectangle in Figures a and b. img166....
Wednesday, March 20, 2013 at 7:48pm

Physics
A flat circular coil with 103 turns, a radius of 3.96 10-2 m, and a resistance of 0.456 Ω is exposed to an external magnetic field that is directed perpendicular to the plane of the coil. The magnitude of the external magnetic field is changing at a rate of ΔB/Δ...
Wednesday, March 20, 2013 at 7:38pm

PHYSICS
8) Which one of the following objects, all initially at the same temperature, will be most efficient in losing heat? a dull black box in vacuum a polished silver box in air a dull black box in air a polished silver box in vacuum
Wednesday, March 20, 2013 at 7:37pm

Physics
The drawing shows a square, each side of which has a length of L = 0.25 m. Two different positive charges q1 and q2 are fixed at the corners of the square. Find the electric potential energy of a third charge q3 = -5 x 10-9 C placed at corner A and then at corner B. q1= 1.5e-9...
Wednesday, March 20, 2013 at 7:30pm

physics
After 35 minutes of running, at the 8-{\rm km} point in a 9-{\rm km} race, you find yourself 200m behind the leader and moving at the same speed. What should your acceleration be if you are to catch up by the finish line? Assume that the leader maintains a constant speed ...
Wednesday, March 20, 2013 at 7:29pm

physics
After 35 minutes of running, at the 8-{\rm km} point in a 9-{\rm km} race, you find yourself 200m behind the leader and moving at the same speed. What should your acceleration be if you are to catch up by the finish line? Assume that the leader maintains a constant speed ...
Wednesday, March 20, 2013 at 7:28pm

Physics MOMENTUM
1) A 1 kg moving at 1 m/s ha s a totally inelastic collision with a 0.7 kg mass. What is the speed of the resulting combined mass after the collision? 2) A 0.010n kg bullet is shot from a 0.500 kg gun at speed of 230 m/s. Find the speed of the gun.
Wednesday, March 20, 2013 at 7:16pm

Physics Impulse
A 2 kg cart rolls across the floor and runs into the wall and sticks. Before the collision the cart has a velocity of 4 m/s in the x direction. The collision took place in 0.1 s. 1) What was the cart's momentum before the collision? 2) What was the cart's KE before the...
Wednesday, March 20, 2013 at 7:12pm

physics
You're in an auto traveling at 25.0m/s toward a pole mounted warning siren. If the siren's frequency is 365 Hz, what frequency do you hear? Use 343m/s as the speed of sound.
Wednesday, March 20, 2013 at 7:12pm

Physics Heat
1) While Laurie is boiling water to cook spaghetti, the phone rings, and all 1.5 kg of water boils away during her conversation.If the water was initially at 15℃, how much heat must have been gained for all of it to turn into a water vapor? 2)By January, the 3.0 kg of ...
Wednesday, March 20, 2013 at 7:04pm

Physics
A) With what minimum speed must you toss a 190 g ball straight up to hit the 15.0 m-high roof of the gymnasium if you release the ball 1.70 m above the ground? Solve this problem using energy. B) With what speed does the ball hit the ground?
Wednesday, March 20, 2013 at 6:59pm

Physics
Heat flow question help?A brass rod with a length of 30.0 cm is placed side by side with an aluminum rod with a length of 30.0 cm and this system is placed between a hot temperature of 100°C and a cold temperature of 10.0°C. The coefficient of thermal conductivities of...
Wednesday, March 20, 2013 at 6:48pm

Physics
Heat flow question help?A brass rod with a length of 30.0 cm is placed side by side with an aluminum rod with a length of 30.0 cm and this system is placed between a hot temperature of 100°C and a cold temperature of 10.0°C. The coefficient of thermal conductivities of...
Wednesday, March 20, 2013 at 6:45pm

Physics
A) With what minimum speed must you toss a 190 ball straight up to hit the 15.0 -high roof of the gymnasium if you release the ball 1.70 above the ground? Solve this problem using energy. B) With what speed does the ball hit the ground?
Wednesday, March 20, 2013 at 6:37pm

physics
A man lifts various loads with the same lever. The distance of the applied force from the fulcrum is 2.00 m and the distance from the fulcrum to the load is 0.500 m. A graph of resistance force vs. effort force is shown. What is the mechanical advantage of the lever? What is ...
Wednesday, March 20, 2013 at 5:55pm

physics
n anti-aircraft gun fires a 23.7 kg shell with a muzzle speed of 880 m/s. What magnitude propulsive force was necessary to attain the muzzle speed within the 5.05 m barrel? (Assume constant acceleration and neglect the Earth's gravitational effect.)
Wednesday, March 20, 2013 at 5:46pm

physics
Light bulb packages will have at least two numbers on them; a power and what the potential difference across the bulb must be so that the bulb has the listed power. You go to the store and purchase two light bulbs. The package for Bulb A says 40 W in a large font with 120 V in...
Wednesday, March 20, 2013 at 5:25pm

A 1.00 kg pendulum bob is released from a height of 0.200 m. Its speed at the bottom of its swing is 1.95 m/s on the first pass. How much energy is lost due to friction during one complete swing of the pendulum? I get Ep=mgh 0.2*9.8*1 =1.96 then i get Ek=1/2mv^2 1/2*1*1.95^2...
Wednesday, March 20, 2013 at 5:19pm

Physics
A small block of mass m slides along the frictionless loop track,if it starts from rest at point p,what us the resultant force acting on it at q?
Wednesday, March 20, 2013 at 4:46pm

physics
The figure below shows a collection of wires. The currents at the numbered points are: I1 = 2.4 mA right; I2 = 3.6 mA down; I3 = 0.60 mA right; I4 = 4.0 mA up; and I5 = 1.6 mA up. i. imgur. com/SCyljHG. png a. What is the current at point A (size and direction)? b. What is the...
Wednesday, March 20, 2013 at 4:35pm

Physics
A layer of oil (n = 1.45) floats on an unknown liquid. A ray of light originates in the oil and passes into the unknown liquid. The angle of incidence is 64.8 degrees, and the angle of refraction is 68.0 degrees. What is the index of refraction of the unknown liquid?
Wednesday, March 20, 2013 at 3:08pm

Physics
A tire 2.0 ft in diameter is placed on a balancing machine where it is spun so that its tread is moving at a constant speed of 51 mph. A small stone is stuck in the tread of the tire. What is the acceleration of the stone as the tire is being balanced?
Wednesday, March 20, 2013 at 3:01pm

AP Physics
Two particles, each of mass m and speed v, travel in opposite directions along parallel lines separated by a distance d. (a) Find an expression for the magnitude L of the angular momentum of the two-particle system around a point midway between the two lines. Use m for the ...
Wednesday, March 20, 2013 at 2:53pm

physics
A 5 kg ball rolls off a 34 m high cliff, and lands 29 m from the base of the cliff. Express the displacement and the gravitational force in terms of vectors and calculate the work done by the gravitational force. Note that the gravitational force is < 0, -mg, 0 >, where ...
Wednesday, March 20, 2013 at 1:52pm

Physics
A rectangular conducting homogeneous (which means the material is the same throughout) block has dimensions 1cm x 2cm x 3cm . A voltage V is applied between all opposite faces of the block and the corresponding currents were recorded. What is the maximum current measured in ...
Wednesday, March 20, 2013 at 1:32pm

Physics
A man seeking to set a world record wants to tow a 122000-kg airplane along a runway by pulling horizontally on a cable attached to the airplane. The mass of the man is 95 kg, and the coefficient of static friction between his shoes and the runway is 0.74. What is the greatest...
Wednesday, March 20, 2013 at 12:52pm

Physics
A rescue helicopter is lifting a man (weight = 797 N) from a capsized boat by means of a cable and harness. (a) What is the tension in the cable when the man is given an initial upward acceleration of 0.711 m/s2? (b) What is the tension during the remainder of the rescue when ...
Wednesday, March 20, 2013 at 12:51pm

physics
A train moves at a speed 72km/hr. When it approaches the station the driver brakes the train stops in 30 minutes. a) what is the value of deceleration? b) what is the duration it takes to stop?
Wednesday, March 20, 2013 at 11:55am

Physics
A man seeking to set a world record wants to tow a 122000-kg airplane along a runway by pulling horizontally on a cable attached to the airplane. The mass of the man is 95 kg, and the coefficient of static friction between his shoes and the runway is 0.74. What is the greatest...
Wednesday, March 20, 2013 at 11:47am

Physics
A rescue helicopter is lifting a man (weight = 797 N) from a capsized boat by means of a cable and harness. (a) What is the tension in the cable when the man is given an initial upward acceleration of 0.711 m/s2? (b) What is the tension during the remainder of the rescue when ...
Wednesday, March 20, 2013 at 11:46am

Physics
A stuntman is being pulled along a rough road at a constant velocity by a cable attached to a moving truck. The cable is parallel to the ground. The mass of the stuntman is 110 kg, and the coefficient of kinetic friction between the road and him is 0.825. Find the tension in ...
Wednesday, March 20, 2013 at 11:45am

physics
After falling from rest from a height of 26 m, a 0.49-kg ball rebounds upward, reaching a height of 16 m. If the contact between ball and ground lasted 1.8 ms, what average force was exerted on the ball?
Wednesday, March 20, 2013 at 10:05am

Physics
A flat circular coil with 103 turns, a radius of 3.96 10-2 m, and a resistance of 0.456 Ω is exposed to an external magnetic field that is directed perpendicular to the plane of the coil. The magnitude of the external magnetic field is changing at a rate of ΔB/Δ...
Wednesday, March 20, 2013 at 9:29am

physics
Susie and Sally are seated on opposing sides of a seesaw. Sally weighs 500 N and is seated a distance of 2 m from the fulcrum (point of rotation). Susie weighs 450 N and is seated a distance of 2.5 m from the fulcrum. Who is being lifted upward?
Wednesday, March 20, 2013 at 9:14am

physics
a loaded cart, mass220-kg is pulled across the ground with the force of300n acting at angle 37 degree with the horizontal. how much work is done in moving the cart 20m?
Wednesday, March 20, 2013 at 8:54am

physics
Let |α⟩=1M√∑M−​1j=0αj|j⟩ and let |β⟩=1M√∑M−​1j=0βj|j⟩ be its QFTM. Suppose we shift the superposition |α⟩ to produce |α′⟩=1M√∑M​&#...
Wednesday, March 20, 2013 at 5:07am

Physics
Okay so i'm having a little trouble explaining the answer to a phys lab question concerning rolling friction: Assuming that f = µN , show that the coefficient of (rolling) friction for the car moving down the inclined plane with a constant speed is given by µ...
Wednesday, March 20, 2013 at 4:07am

physics
1. A piece of rectangular block weighing 5 kg is pressed on a vertical wall by a horizontal force applied to the block. If the coefficient of friction between the block and the wall is 2.0, what force is necessary to keep the block in place? 2. If the force in Prob. 1 is ...
Wednesday, March 20, 2013 at 2:44am

simple PHYSICS!!!
The sun goes around the center of our galaxy once every 250 million years. The sun is also 2.55×10^20 m from the center of our galaxy. What is the acceleration of our sun towards the center of the galaxy in m/s^2?
Wednesday, March 20, 2013 at 1:55am

simple PHYSICS!
The combination of the force of gravity and my hand provide a net force of 40 N on a ball straight up. The ball accelerates at 100 m/s^2 while it is in my hand. What is the mass of the ball in kg?
Wednesday, March 20, 2013 at 1:55am

college physics
If the initial tension in the string is (2.10+/- 0.02)N, what is the tension that would double the wave speed?
Wednesday, March 20, 2013 at 1:28am

Quantum Physics
- What is QFT6 of 1/√2(|0> + |3>? - What is QFT6 of 1/√2(|1> + |4>? - What is QFT6 of 1/√3(|0> + |2> + |4>? - What is QFT6 of 1/√3(|1> + |3> + |5>?
Wednesday, March 20, 2013 at 1:22am

physics
a 3 m long weightless beam is supported at each end by cables. a painter weighing 90 N stands 1 m from the left cable. Calculate the tension in each cable.
Wednesday, March 20, 2013 at 12:11am

physics
Two masses of 8 kg and 12 kg are tied to each end f a string passing over a massless and frictionless pulley. find the resulting accelration of each mass.
Wednesday, March 20, 2013 at 12:04am

physics
A particle starts moving with acceleration 2 m/s2. distance travelled by it in 5th half second is..??
Tuesday, March 19, 2013 at 11:57pm

Physics
Okay so i'm having a little trouble explaining the answer to a phys lab question concerning rolling friction: Assuming that f = µN , show that the coefficient of (rolling) friction for the car moving down the inclined plane with a constant speed is given by µ...
Tuesday, March 19, 2013 at 10:42pm

Physics
How would you derive the formula {-Ff+Fgx=ma} to show that µs=tanè
Tuesday, March 19, 2013 at 8:30pm

Physics - Heat and phase change
Consider a 14.3 g sample of steam initially at 100*C. How many kilojoules equal the amount of energy emitted by this sample as it condenses, cools to it's freezing point, and subsequently freezes to form ice at 0*C
Tuesday, March 19, 2013 at 7:55pm

Physics - Heat and phase change
9.4 kJ of energy is available to take a sample of ice initially at -40*C, heat it to it's melting point, melt it, and subsequently heat it to 50*C. What is the mass, in grams, of the largest such sample for which this amount of energy will suffice?
Tuesday, March 19, 2013 at 7:50pm

Physics - Heat and phase change
8.94 kJ of energy is available to melt 20 g of ice (initially at 0*C) and subsequently to warm the water. What is the water's final temperature in degrees Celsius?
Tuesday, March 19, 2013 at 7:47pm

Physics
Okay so i'm having a little trouble explaining the answer to a phys lab question concerning rolling friction: Assuming that f = µN , show that the coefficient of (rolling) friction for the car moving down the inclined plane with a constant speed is given by µ...
Tuesday, March 19, 2013 at 7:25pm

Physics
A 0.9 kg block is moving with speed 7 m/s towards a spring that has a spring constant of 1.3 N/m. The block hits the spring and compresses it. a) How far did the block compress the spring?(draw a pie graph also) b) When the block is still moving and the spring has been ...
Tuesday, March 19, 2013 at 7:16pm

Physics
A 3.4 kg mass is shot by a sling shot with an initial velocity of 4.5 m/s. When the mass is in the air at a height of 50m, it is still traveling upwards. What is its velocity at that height? Draw energy pie graphs for the initial and final state. (Hint: You will have to use ...
Tuesday, March 19, 2013 at 7:16pm

Physics
A 4 kg weight falls on a spring that is facing up. The weight compresses the spring 0.25m. If the spring constant of the spring is 3.5N/m, how high was the weight when it was dropped?
Tuesday, March 19, 2013 at 7:14pm

Physics
A pendulum is released from some height. When it reaches the bottom of its swing, its speed is 2.5 m/s. What is the initial height of the pendulum?
Tuesday, March 19, 2013 at 7:11pm

Physics
A pendulum is released from some height. When it reaches the bottom of its swing, its speed is 2.5 m/s. What is the initial height of the pendulum?
Tuesday, March 19, 2013 at 7:10pm

physics
Your friend is far-sighted with a near-point distance of 512 cm. What should the focal length be for the lenses in his reading glasses? Assume the glasses are placed 2.0 cm in front of his eyes.
Tuesday, March 19, 2013 at 6:24pm

Physics
What is the moment of force?
Tuesday, March 19, 2013 at 4:38pm

Physics
It is well known that bullets fired at Superman simply bounce off his chest. Suppose that a gangster sprays Superman's chest with bullets of mass m = 2.6 g at a rate of R = 140 bullets/min. The speed of each bullet is v = 510 m/s. Suppose the bullets rebound with no change...
Tuesday, March 19, 2013 at 4:32pm

Physics 11 - Dynamics
While standing on a horizontal frictionless surface a 50.0 kg student pushes against a wall with an average force of 125 N to the right for 0.110 s. Calculate the velocity of this student at 1.110 s. My answer: Vf = 0.275 m/s My solutions book has Vf = -0.275 m/s OR 0.275 m/s ...
Tuesday, March 19, 2013 at 4:30pm

Physics
(1)A battery drives 60c of charge in a circuit for 20s. Thecurrent in the circuit is?(2)What is the volume of a block of expanded polystyrene of 400g and density 16kg/m3?(3)The velocity of a toy car of mass 2kg increased from 5m/s to 10m/s in 2seconds.What force was exerted on...
Tuesday, March 19, 2013 at 4:23pm

Physics
The current in a 5.00mH inductor drops from 2.50A to zero in 5.ooms. What is the average emf induced in he inductor?
Tuesday, March 19, 2013 at 2:21pm

physics
A slide is 5 inches high. it is placed 5.5 inches from the convex lens of a porjection lantern. The image is cast upon a screen 55 inches away. the focal length of the lens is ______inches? b) the heigh of the image cast by the lens is ________inches?
Tuesday, March 19, 2013 at 1:33pm

Physics
A construction worker exerts 209N to move a load of bricks a distance of 10m across the parking lot,how much work does he do?
Tuesday, March 19, 2013 at 12:39pm

Physics
A construction worker exerts 209N to move a load of bricks a distance of 10m across the parking lot,how much work does he do?
Tuesday, March 19, 2013 at 12:39pm

Physics
A construction worker exerts 209N to move a load of bricks a distance of 10m across the parking lot,
Tuesday, March 19, 2013 at 12:38pm

Physics
Sammy Sosa
Tuesday, March 19, 2013 at 12:22pm

Physics
A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 20.7° below the horizontal is applied to the box. The coefficient of kinetic friction between the box and the surface is 0.300. What is the acceleration of the box?
Tuesday, March 19, 2013 at 12:22pm

Physics
What happens to the vibrating length of a resonance tube if a loud speaker is brought close to a displacement node?
Tuesday, March 19, 2013 at 11:33am

a boat can travel 3m/s in still water. a boatman wants to cross a river while covering shortest distance. how long will it take him to cross the river if speed of water is 2m/s
Tuesday, March 19, 2013 at 11:28am

Physics
George pushes a wheelbarrow for a distance of 12 meters at a constant speed for 35 seconds by applying a force of 20 newtons. What is the power applied to push this wheelbarrow? A. 1.2 watts B. 3.4 watts C. 6.9 watts D. 13 watts
Tuesday, March 19, 2013 at 10:05am

physics
compare the relation of fundamental frequencies for a pipe closed at one end and for a pipe open at both ends
Tuesday, March 19, 2013 at 9:12am

physics
find the expression for the acceleration of a cylinder rolling down without slipping on a rough inclined plane also obtained an expression for coefficient of friction
Tuesday, March 19, 2013 at 9:06am

Physics
What is simple pendulum?
Tuesday, March 19, 2013 at 9:01am

Physics
The process of inhalation in the lung may be modelled (very simplistically) by the pV diagram shown below , in which the pressure drops sharply in the lungs at constant volume, followed by expansion at constant pressure, and then finished by the pressure returning to ...
Tuesday, March 19, 2013 at 8:50am

Physics
The process of inhalation in the lung may be modelled (very simplistically) by the pV diagram shown below , in which the pressure drops sharply in the lungs at constant volume, followed by expansion at constant pressure, and then finished by the pressure returning to ...
Tuesday, March 19, 2013 at 8:49am

Physics
How can we find the resultant force if the mass and SPEED are given?? Give me the formula please!!
Tuesday, March 19, 2013 at 8:30am

Physics
How can we find the resultant force if the mass and SPEED are given?? Help me please!!
Tuesday, March 19, 2013 at 8:28am

physics
A(n) 96.1 g ball is dropped from a height of 59.1 cm above a spring of negligible mass.The ball compresses the spring to a maximum displacement of 4.75403 cm. The acceleration of gravity is 9.8 m/s^2. Calculate the spring force constant k. Answer in units of N/
Tuesday, March 19, 2013 at 8:05am

Physics
Two small charged spheres hang from cords of equal length L and make small angles angle1 and angle2 with the vertical. (a) If Q1 = Q, Q2 = 2(Q) and m1 = m2 = m, determine the ratio angle1/angle2. (b)If Q1 = Q, Q2 = 2(Q) and m1 = m,and m2 = 2(m), determine the ratio angle1/...
Tuesday, March 19, 2013 at 7:45am

Physics
Three Point charges have equal magnitudes, two being positive and one negative. These charges are fixed to the corners of an equilateral triangle. As the drawing shows(a) The charge at any one corner experiences forces from the charges at the other corners. Do the individual ...
Tuesday, March 19, 2013 at 7:21am

Physics
Three Point charges have equal magnitudes, two being positive and one negative. These charges are fixed to the corners of an equilateral triangle. As the drawing shows(a) The charge at any one corner experiences forces from the charges at the other corners. Do the individual ...
Tuesday, March 19, 2013 at 7:17am

Physics
Two identical metal spheres have charges of q1 and q2. They are brought together so they touch, and then they are separated. (a) How is the net charge on the two spheres before they touch related to the net charge after they touch? (b) After they touch and are separated, is ...
Tuesday, March 19, 2013 at 7:02am

physics
A parallel beam of light is incident on diverging lens of focal length 12cm. The emergent beam passes through a converging lens of focal length 20cm placed coaxial with it. The beam which finally emerges from the converging lens,comes out parallel. What is the separation of ...
Tuesday, March 19, 2013 at 6:10am

physics
a converging lens has a focal length of 15cm. Find two positions where a real object can produce images four times its size.
Tuesday, March 19, 2013 at 5:58am

physics
a converging lens has a focal length of 15cm. Find two positions where a real object can produce images four times its size.
Tuesday, March 19, 2013 at 5:58am

Physics
A stretched string fixed at both ends is 2.0 m long. What are the three wavelengths that will produce standing waves on this string? Name at least one wavelength that would not produce a standing wave pattern, and explain your answer. I REALLY NEED HELP I DONT UNDERSTAND
Tuesday, March 19, 2013 at 12:07am

Physics
Three cylinders with the same size, density and structure are piled on each other on top of a rough surface. Find the minimum angle which the direction of the force acting between the cylinders and rough surface makes with the vertical?
Tuesday, March 19, 2013 at 12:01am

physics
Why projectiles launched at complimentary angles have the same range?
Monday, March 18, 2013 at 10:18pm

Physics
A charge of -3.66C is fixed at the center of a compass. Two additional charges are fixed on the circle of the compass (radius = 0.0978 m). The charges on the circle are -4.04C at the position due north and +6.20C at the position due east. What is (a) the magnitude and (b) ...
Monday, March 18, 2013 at 10:06pm

physics
A cat is stuck in a tree. You are designated with the job to get it out, yet you do not want to climb the tree, because you may get stuck as well. Instead you set up a pulley system. A rope (consider it massless) runs from the seat you sit on over an ideal pulley and then to ...
Monday, March 18, 2013 at 10:06pm

college physics
for the resonance frequencies: fn=nv/2L If the speed (v) doubles my fn will also doubles ? why?
Monday, March 18, 2013 at 10:03pm

Science (physics)
A particle P is launched from a point O with an initial velocity of 60m/s at an angle of 30 degrees to the horizontal. At the same time, a second particle Q is projected in the opposite direction with initial speed of 50m/s from a point level with point O and 100m from O. You ...
Monday, March 18, 2013 at 9:46pm

Physics
If a 1.0m crowbar is placed uner a 143 kg rock at a point 20.0cm from the end of the bar, what is the IMA of the crowbar?
Monday, March 18, 2013 at 9:45pm

physics
A thin spherical shell of mass M = 2.00 kg is released from rest at the top of an incline of height H=1.31 m and rolls without slipping to the bottom. The ramp is at an angle of θ = 24.1o to the horizontal. Calculate the speed of the sphere's CM at the bottom of the ...
Monday, March 18, 2013 at 7:46pm

PHYSICS
A bottle containing 4 kgof water at a temperature of 15°Cis placed in a refrigerator where the temperature is kept at 2°C.How much heat is transferred from the water to cool it to 2°C?
Monday, March 18, 2013 at 7:29pm

Physics
A bungee jumper (m = 66.00 kg) tied to a 39.00 m cord, leaps off a 69.00 m tall bridge. He falls to 5.00 m above the water before the bungee cord pulls him back up. What size impulse is exerted on the bungee jumper while the cord stretches?
Monday, March 18, 2013 at 7:19pm

physics
A 1.03 kg mass is attached to a spring of force constant 10.6 N/cm and placed on a frictionless surface. By how much will the spring stretch if the mass moves along a circular path of radius 0.525 m at a rate of 2.20 revolutions per second?
Monday, March 18, 2013 at 7:00pm

physics
An aluminum wing on a passenger jet is 38 mlong when its temperature is 23°C.At what temperature would the wing be 2 cm (0.02 m) shorter?
Monday, March 18, 2013 at 6:57pm

Physics
A bungee jumper (m = 66.00 kg) tied to a 39.00 m cord, leaps off a 69.00 m tall bridge. He falls to 5.00 m above the water before the bungee cord pulls him back up. What size impulse is exerted on the bungee jumper while the cord stretches?
Monday, March 18, 2013 at 6:31pm

physics.
1) A racing car has a mass of 1525 kg. What is its kinetic energy if it has a speed of 35 m/s? * 2-3 Conservation of Momentum 2) A 3.0 kg ball is moving at 3 m/s and strikes a 1.5 kg ball moving at -2 m/s. After the collision, the 1.5 kg ball moves to the right at 2 m/s. What ...
Monday, March 18, 2013 at 6:04pm

Physics
Jake has a mass of 88.0 kg and is zooming along in a 110.0-kg bumper car at 9.4 m/s. He bumped Allen's car, which is sitting at rest. Allen has a mass of 88.0 kg. After the elastic collision, Jake continues ahead with a speed of 3.2 m/s. How fast is Allen's car bumped ...
Monday, March 18, 2013 at 5:59pm

Physics
A physics teacher (mass = 84.5 kg) is jogging through the woods and runs straight into a large oak tree at 3.5 m/s. Rebound speed is measured at 2.3 m/s in the opposite direction. If the time of contact with the tree is 45 milliseconds, what is the magnitude of the force that ...
Monday, March 18, 2013 at 5:47pm

Physics
A golf ball with a mass of 50.3 g can be blasted from rest to a speed of 72.1 m/s during impact with a club head. Assume that the impact lasts only about 0.910 ms. Calculate the change in momentum of the ball. Calculate the average force applied.
Monday, March 18, 2013 at 5:45pm

physics
A stone of mass 0.55 kilograms is released and falls to the ground. Measurements show that the stone has a kinetic energy of 9.8 joules at the point of impact with the ground. What is the stone's velocity when it hits the ground?
Monday, March 18, 2013 at 5:43pm

Physics
A set of crash tests consists of running a test car moving at a speed of 12.2 m/s (27.3 mi/hr) into a solid wall. Strapped securely in an advanced seat belt system, a 75.0 kg (165 lbs) dummy is found to move a distance of 0.630 m from the moment the car touches the wall to the...
Monday, March 18, 2013 at 5:34pm

physics
A 7·cm tall candle is placed 125·cm from a lens with a focal length of +25·cm. Note: enter the absolute value of your answers for all distances and heights ... use the signs to determine the type and orientation of the images. a) How far from the lens will...
Monday, March 18, 2013 at 4:15pm

physics
A SUPPOSED TREASURE OF OLD SILVER JEWELRY IS UNCONVERED. a.02M^3 BOX OF THE "OLD JEWELRY" HAS A MASS OF 177KG.IS IT R EALLY OLD SILVER? IF NOT WHAT IS IT?
Monday, March 18, 2013 at 3:29pm

Pages: <<Prev | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | Next>>