Friday

August 29, 2014

August 29, 2014

Number of results: 131

**phyics**

convert 36cm/min to km/h
*April 6, 2010 by alisha*

**phyics**

Calculate (in MeV ) the binding energy per nucleon for 40 Ca .
*December 5, 2011 by paige*

**Phyics**

How far does a 5-kg block with an initial speed of 3 m/s slide up a frictionless 28 incline plane?
*February 17, 2013 by Amy*

**Phyics**

The internal energy change in a system that has absorbed 4 Kcals of heat and 1000 J of work is:
*March 12, 2013 by Miko *

**1th phyics**

A car traveling at 7.5 m/s accelerates 3.4m/s2 to reach a speed of 15.0 m/s. How long does it take for this acceleration to occur?
*September 26, 2010 by Taylor*

**Phyics help please varify the answer is correct **

A parallel circuit has value of RT = R1 // R2 // R3. If one resistor opens, RT RT increases?
*May 31, 2013 by Adam*

**phyics**

find the acceleration if the velocity changes from: a) 2m/s to 4m/s in 4s b) 5m/s to 10m/s in 2s c) 100m/s to 120m/s in 5s d) 86m/s to 94m/s in 4s e) 21m/s to 35m/s in 18s thank you!
*September 19, 2012 by nicky*

**Phyics**

Sue is swinging a yo-yo around her head. What happens to the size of the centripetal acceleration if the mass of the yo-yo is doubled without changing the period or length of the string?
*October 19, 2011 by Eddie*

**phyics**

The choroid and the auricle are similar because, one collects light and the other collects sound?
*April 23, 2009 by Anonymous*

**phyics**

For a given launch velocity, at which launch angle does the projectile undergo the maximum horizontal displacement?
*February 22, 2012 by Lauren01*

**phyics**

a SHO has a maximum speed of 5m/s. How fast will it be going when the potential energy is seven-ninths of the kinetic energy.
*November 13, 2010 by brandy*

**phyics**

calculate the gravitational force between a student with mass (60kg) and her desk (5kg) if she is sitting .2m from her desk
*February 22, 2011 by clayton*

**PHYICS **

A Football is kicked 66.6 meters in 5.39 seconds. What was the initial velocity it was kicked? magnitude and direction above horizontal
*October 17, 2012 by Anthony *

**phyics**

An electron and a proton are placed at rest in a uniform electric field modulus equal to 520N / C. Calculate the speed of each particle of 48 ns after the latter has been released
*January 22, 2014 by Anonymous*

**phyics**

An electron and a proton are placed at rest in a uniform electric field modulus equal to 520N / C. Calculate the speed of each particle of 48 ns after the latter has been released
*January 22, 2014 by Anonymous*

**phyics**

An object in simple harmonic motion has an amplitude of 0.202 m and an oscillation period of 0.620 s. Determine the maximum speed of the motion
*November 12, 2013 by Joey*

**Phyics**

An object in simple harmonic motion has an amplitude of 0.202 m and an oscillation period of 0.620 s. Determine the maximum speed of the motion.
*November 16, 2013 by Corey*

**11th phyics**

An automobile with an initial speed of 4.56 m/s accelerates uniformly at the rate of 2.4 m/s2. Find the final speed of the car after 4.4 s. Answer in units of m/s
*September 26, 2010 by Taylor*

**PHYICS NEED HELP BAD!**

A football is kicked 66.6 meters. If it is in the air for 5.39 seconds, with what initial velocity was it kicked? magnitude and direction above horizontal
*October 17, 2012 by Anthony *

**phyics-universal gravity**

A hypothetical planet has a radius 3.3 times that of Earth, but has the same mass. What is the acceleration due to gravity near its surface? (downward)
*November 3, 2009 by Anonymous*

**PHYICS**

Pick the radioactive isotope in each set 14/7 N OR 23/13 AL EXPLAIN A)its atomic number is greater than 83 B)it has fewer n than p in the nucleus C)it is an odd-odd nuclide none of the above
*September 18, 2010 by Ashley*

**phyics**

Find the horizontal range of a baseball that leaves the bat at an angle of 63 degrees, with the horizontal with an initial velocity of 160 km/hr. discard air resistance
*December 14, 2011 by Brittany*

**PHYICS**

a turn table is turing at a rate of 45 rad/sec and comes to rest after 5 second.how many rotation does it make before coming to rest?
*February 15, 2014 by Pawan*

**phyics**

Pick the radioactive isotope in each set. 23/11 20/9 Explain your choice. a)its atomic number is greater than 83 b)it has fewer n than p in the nucleus c)it is an odd-odd nuclide none of the above
*September 17, 2010 by ashley*

**Phyics**

One of the concrete pillars that supports a house is 1.9 m tall and has a radius of 0.55 m. The density of concrete is about 2.2 x 103 kg/m3. Find the weight of this pillar in pounds (1 N = 0.2248 lb).
*November 12, 2013 by Justin*

**phyics**

A very long 1.75 cm diameter glass rod has one end ground and polished to a convex spherical surface that has a 7.30 cm radius. The glass material has an index of refraction 1.56.
*February 19, 2014 by Anonymous*

**phyics**

You are installing a new spark plug in your car, and the manual specifies that it be tightened to a torque that has a magnitude of 65 Nm. Using the data in the figure, determine the magnitude F of the force that you must exert on the wrench.
*November 1, 2013 by bobby*

**phyics**

The figure shows a person whose weight is W = 500 N doing push-ups. Find the normal force exerted by the floor on (a) each hand and (b) each foot, assuming that the person holds this position.
*November 1, 2013 by bobby*

**Phyics**

A ray of light strikes a mirror at an angle of 26 degrees to the normal. What is the angle of reflection? Answer in units of degrees .
*February 27, 2011 by Maria*

**college phyics**

The position of an object changes with time according to the expression x(t) = 5t62 = 3t - 1. What is the position of the object when its velocity is 11 m/s?
*January 19, 2010 by Mandy*

**phyics-universal gravity**

Calculate the force of gravity on a spacecraft 6400 km (1 earth radii) above the Earth's surface if its mass is 1600 kg.
*November 3, 2009 by DJ*

**phyics**

a 2kg mallet is dropped from a height of .6m onto a nail, driving it 3.5 cm into the wood. What is the average force exerted by the mallet on the nail? thanks
*January 19, 2011 by jinny*

**phyics**

during a process, 21.6 MJ of heat is added to closed system. if the internal energy is increased by 59.6 MJ, how much work in Btu was done? is the work done on ro by the system?
*May 5, 2012 by mikel*

**Phyics**

Given: G = 6.67259 10−11 Nm2/kg2 The acceleration of gravity on the surface of a planet of radius R = 3430 km is 4.43 m/s2.What is the period T of a satellite in circular orbit h = 7683.2 km above the surface? Answer in units of s
*February 7, 2012 by anonymous*

**Phyics please help ms sue **

A 9 v battery is connected across a series combination of 100 W, 35 W, and 55 W resistors. The current measured in the circuit is 100 mA. What can be wrong in this circuit?
*May 31, 2013 by Anonymous*

**Phyics**

A sprinter explodes out of the starting block with an acceleration of + 2.43 m/s2, which she sustains for 1.10 s. Then, her acceleration drops to zero for the rest of the race. What is her velocity at (a)t = 1.10 s and (b) at the end of the race?
*September 24, 2013 by Corey*

**phyics/moon**

The acceleration due to gravity on the Moon's surface is one-sixth that on Earth. What net force would be required to accelerate a 20-kg object at 6.5 m/s2 horizontally on the moon? A) 1.3 N B) 20 N C) 33 N D) 120 N E) 130 N
*June 14, 2010 by sam*

**phyics**

a child playing jacks bounces a super ball on tha sdewalk. The collision is elastic. Does each object have the same kinetic energy after the collision as it did before the collision?
*February 20, 2013 by lynn*

**ssct**

(phyics) question: calculate the final temperature of the water if 400grams of water at 80degress Celsius is poured into a 100grams pot at 30dgrees Celsius .
*December 6, 2012 by arjet*

**phyics**

When you see a traffic light turn red, you apply the brakes until you come to a stop. Suppose your initial speed was 12.9 m/s, and you come to rest in 35.0 m. How much time does this take? Assume constant deceleration.
*October 3, 2012 by Anonymous*

**Phyics**

Could you please check my work, I am not too sure what do. An airplane that flies at 100 km/h with a 10 km/h tailwind travels at 110 km/h relative to the ground. If it instead flies into a 10 km/h headwind, its groundspeed is : 110 km/h /2= 55 km/h
*August 30, 2007 by Soly*

**phyics**

A 0.20-kg object is attached to the end of an ideal horizontal spring that has a spring constant of 120 N/m. The simple harmonic motion that occurs has a maximum speed of 1.1 m/s. Determine the amplitude A of the motion.
*November 12, 2013 by Joey*

**phyics**

A system does 3.7 104 J of work, and 8.5 104 J of heat flows into the system during the process. Find the change in the internal energy of the system.
*March 30, 2014 by minka*

**Phyics**

Three moles of an ideal monatomic gas are at a temperature of 396 K. Then 2438 J of heat is added to the gas, and 897 J of work is done on it. What is the final temperature of the gas?
*November 19, 2013 by Carl*

**Phyics**

Balance the following equations? a) Fe(OH)2 + 2O2 + 3H2O Fe(OH)3 (b) 5Sr + 6H2O 7Sr(OH)2 + 8H2 (c) 9Al + 10Fe3O4 11Al2O3 + 12Fe (d) 13Pb(NO3)2 14PbO + 15NO2 + 16O2 (e) 17O2 + 18N2H4 19H2O2 + 20N2 (f) 21C4H10 + 22O2 23CO2 + 24H2O
*October 16, 2010 by Ashley*

**phyics**

A ball is placed at the top of a hill of incline 60.0 degrees. The ball is allowed to roll for 12.0 seconds. How far will the ball roll during this period? Neglect friction.
*December 18, 2010 by lola*

**phyics**

The position of a 2.75 *10^5 N training helicopter under test is given by r = (0.020 m/s^3)(t^3)i + (2.2 m/s)(t)j - (0.060 m/s^2)(t^2) k Find the net force on the helicopter at t =5.0s. Express your answer in terms of i,j,k. Express your coefficient using two significant figures.
*September 16, 2010 by ami*

**phyics**

Tritium (half-life = 12.3 y) is used to verify the age of expensive brandies. If an old brandy contains only the following fraction of the tritium present in new brandy, how long ago was it produced? 1/16
*September 17, 2010 by ashley*

**phyics**

An object on a vertical spring oscillates up and down in simple harmonic motion with an angular frequency of 25.1 rad/s. Calculate the distance d by which the spring stretches from its unstrained length when the object is allowed to hang stationary from it.
*November 12, 2013 by Joey*

**phyics**

A 11.7-kg uniform board is wedged into a corner and held by a spring at a 50.0 angle, as the drawing shows. The spring has a spring constant of 230 N/m and is parallel to the floor. Find the amount by which the spring is stretched from its unstrained length.
*November 12, 2013 by MATT*

**phyics**

An object on a vertical spring oscillates up and down in simple harmonic motion with an angular frequency of 25.1 rad/s. Calculate the distance d by which the spring stretches from its unstrained length when the object is allowed to hang stationary from it.
*November 12, 2013 by Joey*

**phyics**

A box of mass 0.385 kg slides down a very smooth (frictionless) ramp which is inclined at an angle of 56.6 above the horizontal. What is the acceleration of the box down the ramp?
*September 22, 2012 by Amy*

**Phyics**

A projectile is fired horizontally from a 39 m cliff at 30m/s . Find the speed and velocity of the projectile when it strikes the ground. Find vx Find vy Find v
*October 12, 2011 by Eman*

**phyics**

A projectile is launched horizontally with a speed of 80.0 m/s. If the projectiles is launched above the floor, how long does it take the projectile to hit the floor?
*December 16, 2013 by sydney*

**phyics**

A mechanic pushes a(n) 3980 kg car from rest to a speed of v, doing 5107 J of work in the process. During this time, the car moves 29.3m. Neglect friction between car and road. Find the speed v. Answer in units of m/s.
*February 27, 2011 by leslie*

**phyics**

Who will hear the voice of a singer first-a person in the balcony 50 m away from the stage (Fig. 22-19), or a person 2000 km away at home whose ear is next to the radio? Assume that the microphone is a few centimeters from the singer and the temperature is 20C.
*March 17, 2011 by ami*

**Phyics**

A model rocket blasts off from the ground, rising straight upward with a constant acceleration that has a magnitude of 75.5 m/s2 for 1.58 seconds, at which point its fuel abruptly runs out. Air resistance has no effect on its flight. What maximum altitude (above the ground) ...
*September 25, 2013 by Tracy*

**phyics**

A hand exerciser utilizes a coiled spring. A force of 86.9 N is required to compress the spring by 0.0231 m. Determine the force needed to compress the spring by 0.0432 m.
*November 12, 2013 by Joey*

**Phyics**

A 715N person walks up three flights of stairs, covering a total vertical distance of 10.5(a)If as typical, only 20% of the caloric (food) energy is converted to work by the muscles, how many joules and food calories of energy did the person use
*December 3, 2010 by Anonymous*

**Phyics**

A 17-kg sled is being pulled along the horizontal snow-covered ground by a horizontal force of 28 N. Starting from rest, the sled attains a speed of 2.3 m/s in 10 m. Find the coefficient of kinetic friction between the runners of the sled and the snow.
*September 26, 2013 by Corey*

**phyics**

An airport has runways only 184 m long. A small plane must reach a ground speed of 40 m/s before it can become airborne. What average acceleration must the planes engines provide if it is to take off safely from its airport? Answer in units of m/s2
*October 15, 2013 by cram*

**Phyics**

A hot-air balloon is rising upward with a constant speed of 4.00 m/s. When the balloon is 4.77 m above the ground, the balloonist accidentally drops a compass over the side of the balloon. How much time elapses before the compass hits the ground?
*September 25, 2013 by Tracy*

**Phyics**

A hot-air balloon is rising upward with a constant speed of 4.00 m/s. When the balloon is 4.77 m above the ground, the balloonist accidentally drops a compass over the side of the balloon. How much time elapses before the compass hits the ground?
*October 20, 2013 by Johnny*

**phyics**

A person who weighs 829 N steps onto a spring scale in the bathroom, and the spring compresses by 0.538 cm. (a) What is the spring constant? (b) What is the weight of another person who compresses the spring by 0.390 cm?
*November 5, 2013 by bobby*

**phyics**

When responding to sound, the human eardrum vibrates about its equilibrium position. Suppose an eardrum is vibrating with an amplitude of 5.0 x10-7 m and a maximum speed of 3.3 x10-3 m/s. (a) What is the frequency (in Hz) of the eardrum's vibrations? (b) What is the maximum ...
*November 12, 2013 by Joey*

**phyics**

Richard is driving home to visit his parents. 125 of the trip are on the interstate highway where the speed limit is 65 . Normally Richard drives at the speed limit, but today he is running late and decides to take his chances by driving at 72 . how do i get to my answer
*September 11, 2012 by tamika*

**Phyics**

A ship is first seen on a radar screen to be 13 km east of the radar site. Some time later, the ship is at 16 km northwest. What is the displacement of the ship from the first location it is seen at?
*September 9, 2010 by G*

**Phyics - Astronomy**

You are standing at a latitude of 35 degrees South. Star x is currently at an azimuth of 45 degrees and an altitude of 50 degrees. What is the azimuth and altitude coordinates of Star X 3 hours later? I don't know how to do this. If anyone knows how to calculate this please ...
*September 11, 2011 by Amanda*

**phyics**

A simple pendulum is made from a 0.781-m-long string and a small ball attached to its free end. The ball is pulled to one side through a small angle and then released from rest. After the ball is released, how much time elapses before it attains its greatest speed?
*November 12, 2013 by MATT*

**Phyics**

The average distance between Earth and the sun is 1.50e8 km. Calculate the average speed, in km/h, of Earth assuming a circular path about the sun. Use the equations v = 2r/T. Please ignore this question and view the question I have a few spaces above. The equation was not ...
*August 16, 2007 by Jayd*

**Phyics**

The leader of a bicycle race is traveling with a constant velocity of +11.9 m/s and is 10.7 m ahead of the second-place cyclist. The second-place cyclist has a velocity of +9.30 m/s and an acceleration of +1.20 m/s2. How much time elapses before he catches the leader?
*September 12, 2013 by Antonio*

**phyics**

on a warm day(92 degrees F) an air filled balloon occupies a volume of .20m^3 and is under a pressure of 20.0 lbs/in^2. if the baloon is cooled to 32 degrees F in a refigerator while its pressure is reduced to 14.7 lb/in wat is the volume on the air in the container? (assume ...
*February 28, 2010 by Standard C.*

**Phyics**

A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 5.48 m/s. The car is a distance d away. The bear is 30.5 m behind the tourist and running at 6.67 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
*September 23, 2013 by I NEED HELP PLZ!!!*

**phyics**

Ethyl alcohol has been added to 190 {\rm mL} of water in a container that has a mass of 140 {\rm g} when empty. The resulting container and liquid mixture has a mass of 450 {\rm g}. What volume of alcohol was added to the water? Express your answer using two significant figures.
*December 4, 2011 by please help*

**phyics**

A novice golfer on the green takes three strokes to sink the ball. The successive dis- placements are 5.9 m to the north, 10 m 45 north of east, and 5.9 m 26 west of south. Starting at the same initial point, an expert (lucky) golfer could make the hole in a single ...
*November 17, 2011 by robert*

**phyics help nedded**

In the figure below, three ballot boxes are connected by cords, one of which wraps over a pulley having negligible friction on its axle and negligible mass. The masses are mA = 24.0 kg, mB = 40.0 kg, mC = 30.0 kg. (a) When the assembly is released from rest, what is the ...
*October 19, 2012 by some one *

**Phyics**

One afternoon, a couple walks three-fourths of the way around a circular lake, the radius of which is 2.16 km. They start at the west side of the lake and head due south to begin with. (a) What is the distance they travel? (b) What is the magnitude of the couples displacement...
*September 23, 2013 by I NEED HELP PLZ!!! Thanks!!!*

**phyics**

In an historical movie, two knights on horseback start from rest 94.3 m apart and ride directly toward each other to do battle. Sir George's acceleration has a magnitude of 0.273 m/s2, while Sir Alfred's has a magnitude of 0.280 m/s2. Relative to Sir George's starting point, ...
*September 23, 2013 by question*

**Phyics**

In an historical movie, two knights on horseback start from rest 94.3 m apart and ride directly toward each other to do battle. Sir George's acceleration has a magnitude of 0.273 m/s2, while Sir Alfred's has a magnitude of 0.280 m/s2. Relative to Sir George's starting point, ...
*September 24, 2013 by question*

**phyics (PLEASE PLEASE READ)**

a model rocket rises with constant accerleration to a height of 3.2 m, at which point its speed is 26.0 m/s. (a) how much time does it take for the rocket to reach this height? (b) what was the magnitude of the rocket's acceration? (c) find the height and speed of the rocket 0...
*November 20, 2011 by taylor*

**Phyics**

A rubber ball with a radius of 4.8 cm rolls along the horizontal surface of a table with a constant linear speed v. When the ball rolls off the edge of the table, it falls 0.83 m to the floor below. If the ball completes 0.68 revolutions during its fall, what was its linear ...
*October 19, 2008 by Andrew*

**Phyics **

You are driving a 2520.0 kg car at a constant speed of 14.0 m/s along an icy, but straight, level road. As you approach an intersection, the traffic light turns red. You slam on the brakes. Your wheels lock, the tires begin skidding, and the car slides to a halt in a distance ...
*February 28, 2011 by Moha*

**Phyics**

A Carnot engine has 200 g of helium as its working substance and operates between two reservoirs which are at temperatures of 500C and 30C. The initial volume of the gas is 20 litres while the volume after isothermal expansion is 60 litres. For one complete ...
*July 21, 2010 by Physics*

**phyics mc Q**

Q:Which of the following are expressions for a type of potential energy? ( this question can have more than one answer !!!! ) a)mg(h_F-h_i) b)F_f*d c)(1/2)mv^2 d)(1/2)k*(final_x^2-initial_x^2) Q: If you are trying to figure out how high you can jump, which of the following ...
*May 22, 2012 by emmie*

**PHYICS**

A car moving with constant speed in a circular path experience a centripetal acceleration if speed of car increases by three factors but the circular path remain same.What is the new centripetal acceleration in term of original ac?
*February 15, 2014 by Pawan*

**phyics**

A train at a constant 44.0 km/h moves east for 42 min, then in a direction 45.0 east of due north for 17.0 min, and then west for 51.0 min. What are the (a) magnitude (in km/h) and (b) angle (relative to north, with east of north positive and west of north negative) of its ...
*October 10, 2012 by D*

**phyics**

Objects of equal mass are oscillating up and down in simple harmonic motion on two different vertical springs. The spring constant of spring 1 is 175 N/m. The motion of the object on spring 1 has twice the amplitude as the motion of the object on spring 2. The magnitude of the...
*November 12, 2013 by MATT*

**phyics**

i need help setting it up to find the answers. (answers included) two masses are connected together by a string which is then hung over a pulley. m1= 7.50 kg and m2= 6.50 kg. before they are released m1 is suspended h= 135cm above the floor while m2 is sitting on the floor. a....
*November 1, 2010 by danielle*

**phyics**

A ball is thrown straight upward. At 5.00 m above its launch point, the balls speed is one-half its launch speed. What maximum height above its launch point does the ball attain?
*October 20, 2013 by Johnny*

**Phyics**

A 1390-N uniform beam is attached to a vertical wall at one end and is supported by a cable at the other end. A 1960-N crate hangs from the far end of the beam. Using the data shown in the figure, find (a) the magnitude of the tension in the wire and the magnitudes of the (b) ...
*November 10, 2013 by Johnson*

**phyics**

A glass bottle of soda is sealed with a screw cap. The absolute pressure of the carbon dioxide inside the bottle is 1.60 x 105 Pa. Assuming that the top and bottom surfaces of the cap each have an area of 3.60 x 10-4 m2, obtain the magnitude of the force that the screw thread ...
*November 12, 2013 by John*

**algebra phyics word problem**

at 20 degree C the speed of sound in air is 344 m/s. This is 1.117 m/s slower than the speed of sound in water. write and solve an equation to find the speed of sound in water. i started writeing this but im not sure how to do this: 344 - s = 344 im not sure how to do this?
*October 15, 2011 by marko*

**Phyics**

A uniform board is leaning against a smooth vertical wall. The board is at an angle above the horizontal ground. The coefficient of static friction between the ground and the lower end of the board is 0.710. Find the smallest value for the angle , such that the lower end of ...
*November 10, 2013 by Bobby*

**phyics**

A 0.2 kg plastic ball moves with a velocity of 1.5 m/s. It collides with a second plastic ball of mass 1.8 kg, which is moving along the same line at a speed of 0.1 m/s. After the collision, both balls continue moving in the same, original direction. The speed of the 1.8 kg ...
*April 11, 2013 by MEEEEE*

**Phyics**

A 49-N crate is suspended from the left end of a plank. The plank weighs 21 N, but it is not uniform, so its center of gravity does not lie halfway between the two ends. The system is balanced by a support that is 0.30 m from the left end of the plank. How far to the right of ...
*November 10, 2013 by Bobby*

**phyics**

A car is traveling at a constant speed of 31.8 m/s on a highway. At the instant this car passes an entrance ramp, a second car enters the highway from the ramp. The second car starts from rest and has a constant acceleration. What acceleration must it maintain, so that the ...
*September 24, 2013 by larry*

**phyics**

If two cars are traveling along a straight road, one behind the other. the first is traveling at a constant velocity of 10 m/s. the second, approaching from the rear, is traveling at 22 m/s. when the second car is 300m behind the first, the driver applies the brakes, ...
*November 6, 2010 by billy*

**phyics (PLEASE PLEASE READ)**

a bicyclist is finishing his repair of a flat tire when a friend rides by at 3.5 m/s. two seconds later, the bicyclist hops on his bike and accelerates at 2.4 m/s^2 until he catches his friend? (a) how much time does it take until he catches his friend? (b) how for has he ...
*November 20, 2011 by taylor*

**Phyics**

1)A logging truck is dragging a 427 kg log through the forest at a constant speed of 3.5 m/s. If the truck is applying a force of 1047 N to the log to keep it moving, what is the coefficient of friction between the log and the ground? im thinking you use the kinetic friction...
*October 31, 2009 by Anonymous*

**Phyics**

A π- ("pi-minus") particle, which has charge -e, is at location 3.00e10-9, -2.00e10-9, -3.00e10-9 m. What is the electric field at location < -3.00e10-9, 3.00e10-9, 4.00e10-9> m, due to the π- particle?
*January 16, 2014 by Jaden*