Tuesday

September 2, 2014

September 2, 2014

**Recent Homework Questions About Physics**

Post a New Question | Current Questions

**physics**

An iorn rod (a=11.8 x 10^-6 C^-1) has a length of 1000 meters(or 1 km) at 0 degrees Celsius. If the rod must expand 10 cm to bridge a gap, to what temperature must the rod be heated?
*Thursday, August 1, 2013 at 10:46am*

**physics**

if a skydiver with a surface area of 2m sq falls at a steady speed of 55m/s with a force of 900N what is the pressure on her?
*Thursday, August 1, 2013 at 9:50am*

**physics-magnetism**

The direction of magnetic lines of force change if an iron piece is placed in its field. Why?
*Wednesday, July 31, 2013 at 11:23pm*

**physics-optics**

The index of refraction of Ruby is less than the index of refraction of diamond. Why?
*Wednesday, July 31, 2013 at 11:21pm*

**physics**

(a) By what factor is one sound more intense than another if the sound has a level 17.0 dB higher than the other? (b) If one sound has a level 32.0 dB less than another, what is the ratio of their intensities?
*Wednesday, July 31, 2013 at 10:17pm*

**physics**

An 8 hour exposure to a sound level of 95.0 dB may cause hearing damage. What energy in joules falls on a 0.850 cm diameter eardrum so exposed?
*Wednesday, July 31, 2013 at 10:16pm*

**physics**

The amplitude of a sound wave is measured in terms of its maximum gauge pressure. By what factor does the amplitude of a sound wave increase if the sound level goes up by 38.0 dB?
*Wednesday, July 31, 2013 at 10:16pm*

**physics**

19 cars in a circle at a boom box competition produce a 130 dB sound level at the center of the circle. What is the average sound level(dB) produced there by each, assuming interference effects can be neglected?
*Wednesday, July 31, 2013 at 10:16pm*

**physics**

A physicist at a fireworks display times the lag between seeing an explosion and hearing its sound, and finds it to be 0.800 s. (a) How far away(m) is the explosion if air temperature is 22.0°C, neglecting the time taken for light to reach the physicist? (b) How much ...
*Wednesday, July 31, 2013 at 10:15pm*

**physics**

if you continue to lower the water level after recording length at the first sound resonance at fixed tuning fork frequency, you will hear the sound again but the sound gets louder(seond resonance). at this point, by what factor has length increased? why?
*Wednesday, July 31, 2013 at 7:59pm*

**Physics**

An iorn rod (a=11.8 x 10^-6C^-1) has a length of 1000 meters(or 1 km) at 0 degrees Celsius. If the rod must expand 10 cm to bridge a gap, to what temperature must the rod be heated?
*Wednesday, July 31, 2013 at 7:49pm*

**physics**

An 8 hour exposure to a sound level of 95.0 dB may cause hearing damage. What energy in joules falls on a 0.850 cm diameter eardrum so exposed?
*Wednesday, July 31, 2013 at 6:27pm*

**physics**

The amplitude of a sound wave is measured in terms of its maximum gauge pressure. By what factor does the amplitude of a sound wave increase if the sound level goes up by 38.0 dB?
*Wednesday, July 31, 2013 at 6:26pm*

**physics**

19 cars in a circle at a boom box competition produce a 130 dB sound level at the center of the circle. What is the average sound level(dB) produced there by each, assuming interference effects can be neglected?
*Wednesday, July 31, 2013 at 6:26pm*

**physics**

(a) By what factor is one sound more intense than another if the sound has a level 17.0 dB higher than the other? (b) If one sound has a level 32.0 dB less than another, what is the ratio of their intensities?
*Wednesday, July 31, 2013 at 6:26pm*

**physics**

A physicist at a fireworks display times the lag between seeing an explosion and hearing its sound, and finds it to be 0.800 s. (a) How far (m)away is the explosion if air temperature is 22.0°C, neglecting the time taken for light to reach the physicist? (b) How much ...
*Wednesday, July 31, 2013 at 5:58pm*

**Physics**

A boiler furnace releases 10000.000kJ of heat for each kg of fuel burned and produces dry saturated steam at 10000.000kPa from feed water at 190.000 degrees Celsius. How many kg of steam will be produced for each kg of fuel burned if the boiler had an efficiency of 69%? ANS = ...
*Wednesday, July 31, 2013 at 3:06pm*

**Physics**

The figure below shows two springs connected in parallel. This combination can be thought of as being equivalent to a single spring having an effective force constant keff. Obviously, the effective force constant must be related to the force constants k1 and k2 of the ...
*Wednesday, July 31, 2013 at 1:50pm*

**Physics**

The figure below shows two springs connected in parallel. This combination can be thought of as being equivalent to a single spring having an effective force constant keff. Obviously, the effective force constant must be related to the force constants k1 and k2 of the ...
*Wednesday, July 31, 2013 at 1:50pm*

**physics**

a boy tosses a coin upward with a velocity of 14.7 m/s. a. find the maximum height reached by the coin. b. time of flight c. velocity when the coin returns to the hand d. suppose the boy failed to catch the coin and the coin goes to the ground, with what velocity will it ...
*Wednesday, July 31, 2013 at 4:50am*

**physics**

A simple pendulum consists of a ball connected to one end of a thin brass wire. The period of the pendulum is 2.15 s. The temperature rises by 133 C°, and the length of the wire increases. Determine the change in the period of the heated pendulum.
*Tuesday, July 30, 2013 at 10:28pm*

**physics**

The Eiffel Tower is a steel structure whose height increases by 19.5 cm when the temperature changes from -9 to +41 oC. What is the approximate height (in meters) at the lower temperature?
*Tuesday, July 30, 2013 at 10:23pm*

**physics**

The latent heat of fusion for water is 33.5 × 104 J/kg, while the latent heat of vaporization is 22.6 × 105 J/kg. What mass m of water at 0 °C must be frozen in order to release the amount of heat that 2.32 kg of steam at 100 °C releases when it condenses?
*Tuesday, July 30, 2013 at 10:22pm*

**Physics**

A uniform beam of length L = 7.80 m and weight 4.05 102 N is carried by two workers, Sam and Joe, as shown in the figure below. Determine the force that each person exerts on the beam. (Sam is 1m from one end of beam and joe is 2m from the opposite end.)
*Tuesday, July 30, 2013 at 7:51pm*

**physics**

Show that 60.0 L of gasoline originally at 15.0ºC will expand to 61.1 L when it warms to 35.0ºC, how much gasoline has spilled by the time they warm to 35.0ºC ?
*Tuesday, July 30, 2013 at 7:30pm*

**physics**

(a) A solar collector is 12.0% efficient in gathering solar energy and converting it to heat. If the average intensity of sunlight on one day is 700 W/m2, what area(m^2) should your collector have to gather energy at the rate of 150 W? (b) What is the maximum cost ($)of the ...
*Tuesday, July 30, 2013 at 5:14pm*

**physics**

What is the wavelength (m)of an earthquake that shakes you with a frequency of 11.5 Hz and gets to another city 85.0 km away in 12.0 s?
*Tuesday, July 30, 2013 at 5:11pm*

**physics**

How many times a minute does a boat bob up and down on ocean waves that have a wavelength of 43.0 m and a propagation speed of 5.25 m/s?
*Tuesday, July 30, 2013 at 5:10pm*

**Physics**

Use the PV diagram of a system. The units for P and V are atmospheric pressure atm and liter L. Process A to B and B to C are straight lines on it. How much is the work done by the system from A to C in J? Given these coordinates:(volume on the x, pressure on the y) A: (1 Li, ...
*Tuesday, July 30, 2013 at 3:52pm*

**physics**

A ball of mass 8 kg is thrown vertically upward from the ground , with an initially velocity of 25 m/s. Determine the maximum height to which it will travel if atmospheric resistance is neglected.
*Tuesday, July 30, 2013 at 12:49pm*

**applied physics**

incline plane numerical
*Tuesday, July 30, 2013 at 12:19pm*

**Physics**

A simple pendulum consists of a ball connected to one end of a thin brass wire. The period of the pendulum is 1.45 s. The temperature rises by 142 C°, and the length of the wire increases. Determine the change in the period of the heated pendulum.
*Tuesday, July 30, 2013 at 9:14am*

**physics**

A U.S quarter is rolling on the floor without slipping in such a way that it describes a circular path of radius R=4 cm. The plane of the coin is tilted at an angle of θ=45∘ with respect to the horizontal plane (see the figure below). Find the coin's period T in...
*Tuesday, July 30, 2013 at 5:54am*

**Physics **

a cylinder of gas is at a room temp (20 c) the air conditioner breaks down and the tempture rises to 58c what is the new pressure of the gas relative to its initial pressure?
*Tuesday, July 30, 2013 at 12:26am*

**physics**

A projectile is launched over level ground at a launch angle of 70o with an initial velocity vo. At some later time while the projectile is on its way to the peak in its trajectory, its velocity vector makes an angle of 50o with respect to the horizontal. What is the magnitude...
*Monday, July 29, 2013 at 11:22pm*

**physics**

A 5-kg block of ice is at a temperature of -27 °C. How much heat must be added to the ice to produce 5 kg of liquid water with a final temperature of 35 oC?
*Monday, July 29, 2013 at 11:16pm*

**physics**

A 1.0-m thin rod of aluminum is laid end-to-end with a 1.0-m thin rod of steel. The rods are initially at 25 oC. What is the total length of both rods when heated to 450 oC?
*Monday, July 29, 2013 at 11:15pm*

**physics**

A cube of balsa wood (side length = 0.25 m) is tied with a string to the bottom of a waterfilled container. The wood is completely immersed. What is the tension in the string?
*Monday, July 29, 2013 at 11:11pm*

**physics**

What is the absolute pressure at the bottom of a storage tank of oil 18-m deep that is open to the atmosphere? Take the density of oil to be 800 kg/m3.
*Monday, July 29, 2013 at 11:06pm*

**physics**

If the input piston of a hydraulic jack has a radius of 0.005 m, what force is necessary to apply to it to lift a 1500-kg car on the output piston whose radius is 0.5 m?
*Monday, July 29, 2013 at 10:15pm*

**physics**

The loudest sound in Earth’s history is believed to be the explosion of the volcanic island of Krakatoa, back in 1883. Physicists estimate that the intensity of the sound produced was 1.0×107 W/m2. How many decibels does this correspond to?
*Monday, July 29, 2013 at 10:13pm*

**physics**

A string of length 10.0 m is tied between two posts and plucked. This sends a wave down the string moving at a speed of 130 m/s with a frequency of 215 Hz. How many complete wavelengths of this wave will fit on the string?
*Monday, July 29, 2013 at 10:08pm*

**physics**

Suppose you are stopped for a traffic light, and a fast ambulance approaches you from behind with a speed of 34.0 m/s. The siren on the ambulance produces sound with a frequency of 960 Hz. The speed of sound in air is 343 m/s. What is the wavelength of the sound reaching your ...
*Monday, July 29, 2013 at 10:06pm*

**physics**

Using a small pendulum of length 0.171 m, a geophysicist observes that it completes 1 cycle every 0.833 s. What is the value of g at his location?
*Monday, July 29, 2013 at 9:57pm*

**physics**

Socola and Brooke are balanced on a teeter-totter plank as shown below. Socola has a mass of 7.7 kg, and Brooke’s mass is 53 kg. Brooke is located 1.0 m from the pivot. Assume the plank is massless, and calculate how far Socola is from the pivot (x).
*Monday, July 29, 2013 at 9:55pm*

**physics**

A roller coaster at an amusement park has a dip that bottoms out in a vertical circle of radius 11.0 m. A passenger feels the seat of the car pushing upward on her with a force equal to three times her weight at the bottom of the dip. What is her speed as she goes through the ...
*Monday, July 29, 2013 at 9:46pm*

**physics**

The angular speed of the rotor in a centrifuge decreases from 226 to 186.0 rev/s with an angular deceleration of 6.4 rev/s2. During this period, how many revolutions does the rotor turn?
*Monday, July 29, 2013 at 9:44pm*

**physics**

An SUV with a mass of 1.80×103 kg is travelling eastbound with a speed of +15.0 m/s, while a compact car with a mass of 9.00×102 kg is travelling westbound at -15.0 m/s. The vehicles collide head-on and stick together. What is the speed of the wreck immediately ...
*Monday, July 29, 2013 at 9:42pm*

**Physics - Magnetism**

The direction of magnetic lines of force change if an iron piece is placed in its field. Why?
*Monday, July 29, 2013 at 5:21pm*

**physics**

A 100-N mass on a horizontal table is connected to a 50.0-N hanging mass over a frictionless pulley. The two masses are moving at constant speed. What is the value of the coefficient of kinetic friction between the table and the horizontal mass?
*Monday, July 29, 2013 at 3:12pm*

**physics**

A rocket is used to place a satellite in orbit about a planet. The velocity of the satellite is 534 m/s and the radius of orbit is 1.21×108 m. What is the mass of planet?
*Monday, July 29, 2013 at 3:11pm*

**physics**

as i have known that centripetal force is directly proportional to the angular speed square. so, what is the relationship between angular speed and centripetal force ? when centripetal force increase, does angular speed increase too? i need more explanation.
*Monday, July 29, 2013 at 2:43pm*

**physics**

A 2.0-m-tall basketball player is standing on the floor a distance d from the basket, as shown in the figure below. He shoots the ball at an angle of 40.0o above the horizontal with a speed of 10.67 m/s and makes the shot. The height of the basket is 3.05 m. What is d?
*Monday, July 29, 2013 at 1:39pm*

**physics**

A diver springs vertically upward with an initial speed of 1.7 m/s from a diving board that is 3.2 m above the water. Find the speed with which she enters the water, assuming completely vertical motion.
*Monday, July 29, 2013 at 1:34pm*

**physics**

Two golf balls are thrown with the same speed off the top of a large bridge at the same time. Ball A is thrown straight downward, and Ball B is thrown horizontally off the bridge. Which ball hits the ground first?
*Monday, July 29, 2013 at 1:13pm*

**physics**

An LSU football defender is 6 m behind a Georgia Tech receiver who has the football and is d meters from making a touchdown. If the LSU player is running at 5 m/s and the receiver is running at 4 m/s, what is the furthest distance, d, that the Tech player can be from the goal ...
*Monday, July 29, 2013 at 1:07pm*

**physics**

During a hard sneeze, your eyes will shut for 0.5 s. If you are driving a car at 90 km/h during such a sneeze, how far does the car move during that time?
*Monday, July 29, 2013 at 12:20pm*

**physics**

A U.S quarter is rolling on the floor without slipping in such a way that it describes a circular path of radius R=4 cm. The plane of the coin is tilted at an angle of θ=45∘ with respect to the horizontal plane. Find the coin's period T in seconds, that is, the ...
*Monday, July 29, 2013 at 8:08am*

**physics**

A rugby player kicks a ball from a ground aiming to get the ball over rhe horizontal bar and betwween the vertical posts. the ball is 50 m away from goal line, directly infront of a goal, and the initial speed of the ball is 25 m/s. The horizontal bar is 3.5 from the ground. ...
*Monday, July 29, 2013 at 5:51am*

**physics**

motion that has no acceleration 13 letters only
*Monday, July 29, 2013 at 5:41am*

**Physics**

A wire is bent into the shape of an planar Archimedean spiral which in polar coordinates is described by the equation r=bθ. The spiral has N=100 turns and outer radius R=10 cm (R is the distance from point O to point T). Note that in the figure below we show a spiral ...
*Monday, July 29, 2013 at 5:38am*

**physics**

Our muscles atrophy when there is no gravitational force. On long space flights this is a problem, which is why astronauts exercise. On very long space flights it might be advisable to simulate gravity. Your space ship is a long cylinder of radius 100 m that spins about its ...
*Monday, July 29, 2013 at 5:37am*

**physics**

When a pendulum with a period of 2.00000 s is moved to a new location from one where the acceleration of gravity was 9.80 m/s2, its new period becomes 1.99711 s. By how much does the acceleration of gravity differ at its new location? (m/s2)
*Sunday, July 28, 2013 at 9:44pm*

**physics**

Two parakeets sit on a swing with their combined center of mass 15.0 cm below the pivot. At what frequency do they swing?
*Sunday, July 28, 2013 at 9:43pm*

**physics**

Suppose a diving board with no one on it bounces up and down in a simple harmonic motion with a frequency of 3.00 Hz. The board has an effective mass of 10.0 kg. What is the frequency of the simple harmonic motion of a 62.0 kg diver on the board?
*Sunday, July 28, 2013 at 9:43pm*

**physics**

A U.S quarter is rolling on the floor without slipping in such a way that it describes a circular path of radius R=4 cm. The plane of the coin is tilted at an angle of θ=45∘ with respect to the horizontal plane (see the figure below). Find the coin's period T in...
*Sunday, July 28, 2013 at 9:36pm*

**Physics**

Help with the following ones: 2-2-1, 2-2-3, 2-2-4 Q2_1: QUIZ 2, PROBLEM #1 The shaft ABC is a solid circular cylinder of constant outer diameter 2R and length 3L. The shaft is fixed between walls at A and C and it is composed of two segments made of different materials. The ...
*Sunday, July 28, 2013 at 8:55pm*

**physics**

When 1.60 multiplied by 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature?
*Sunday, July 28, 2013 at 5:35pm*

**physics**

Calculate the net work output of a heat engine following path ABCDA in Figure 14.30, where horizontal axis is V and each unit is 0.5*10^-3 m^3, V1 = 1.0*10^-3 m^3 and V2 = 4.0*10^-3 m^3. The vertical axis is P(N/m^2); A is (1.0*10^-3,2.6*10^6), B is (4.0*10^-3,2.0*10^6), C is...
*Sunday, July 28, 2013 at 5:34pm*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...
*Sunday, July 28, 2013 at 5:34pm*

**physics**

(a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by 107 J of work (10...
*Sunday, July 28, 2013 at 5:34pm*

**physics**

When 1.60 multiplied by 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature (C)? I use delta S = entropy change = 1.6*10^5*[1/293 - 1/T2] = 470 Solve for T2, but it's not correct. Please someone help me...
*Sunday, July 28, 2013 at 4:14pm*

**physics**

(a) How much heat flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change in entropy due to this heat transfer? (c) How much work is made unavailable, taking the lowest temperature to...
*Sunday, July 28, 2013 at 3:53pm*

**physics**

When 1.60 multiplied by 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature?
*Sunday, July 28, 2013 at 3:53pm*

**physics**

0.460 kg mass suspended from a spring oscillates with a period of 1.50 s. How much mass must be added to change the period to 1.95 s?
*Sunday, July 28, 2013 at 3:50pm*

**physics**

A 0.810 m long brass pendulum experiences a 18.0°C temperature increase. (a) Calculate the original period(s). (b) What is the change in the period(s)? (c) Find the ratio of the change in period to the original period, and calculate how long (h) a clock run by this ...
*Sunday, July 28, 2013 at 3:38pm*

**physics**

A spring has a length of 0.190 m when a 0.300 kg mass hangs from it, and a length of 0.750 m when a 2.80 kg mass hangs from it. (a) What is the force constant of the spring? (b) What is the unloaded length(m) of the spring?
*Sunday, July 28, 2013 at 12:57pm*

**physics**

(a) A bathroom scale has a spring that is compressed by 1.50 cm when a 165 kg person stands on the scale. Assuming the spring is described by Hooke's law, find its force constant. (b) How much would it be compressed if a 94.0 kg person stands on the scale in an elevator ...
*Sunday, July 28, 2013 at 12:56pm*

**physics**

A pendulum with a bob of mass 30g is lifted to height of 5.00cm above its lowest point and allowed to fall so that collides elastically with a block of mass 20g that rests on a smooth horizontal floor. The block stops 5 seconds after the collision. Assuming no sound is ...
*Sunday, July 28, 2013 at 10:22am*

**Physics - optics**

the index of refraction of ruby is less than the index of refraction of diamond, Why?
*Sunday, July 28, 2013 at 10:18am*

**physics**

Two boys and their father are balance on a seesaw. The father, 70kg, sits on one end 0.65m from the center of the seesaw while the two boys sit together on the other end. If each boy weighs 30kg, where should they sit?
*Sunday, July 28, 2013 at 5:00am*

**physics**

Two boys and their father are balance on a seesaw. The father, 70kg, sits on one end 0.65m from the center of the seesaw while the two boys sit together on the other end. If each boy weighs 30kg, where should they sit?
*Sunday, July 28, 2013 at 4:59am*

**physics**

Two boys and their father are balance on a seesaw. The father, 70kg, sits on one end 0.65m from the center of the seesaw while the two boys sit together on the other end. If each boy weighs 30kg, where should they sit?
*Sunday, July 28, 2013 at 4:58am*

**physics**

A spring has a length of 0.260 m when a 0.300 kg mass hangs from it, and a length of 0.750 m when a 1.90 kg mass hangs from it.(a) What is the force constant of the spring?(b) What is the unloaded length of the spring?
*Sunday, July 28, 2013 at 1:34am*

**physics**

While taking a plane flight to a meeting, a physicist decides to do a mental calculation of how much fuel the plane would consume in the absence of friction, assuming its engines have an efficiency of 22.0% and the mass of the plane is 200,000 kg. Each gallon of jet fuel ...
*Sunday, July 28, 2013 at 1:33am*

**physics**

(a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by 107 J of work (10...
*Sunday, July 28, 2013 at 1:33am*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...
*Sunday, July 28, 2013 at 1:33am*

**physics**

When 1.60 multiplied by 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature (C)?
*Sunday, July 28, 2013 at 1:32am*

**physics**

Calculate the net work output of a heat engine following path ABCDA in Figure 14.30, where horizontal axis is V and each unit is 0.5*10^-3 m^3, V1 = 1.0*10^-3 m^3 and V2 = 4.0*10^-3 m^3. The vertical axis is P(N/m^2); A is (1.0*10^-3,2.6*10^6), B is (4.0*10^-3,2.0*10^6), C is...
*Sunday, July 28, 2013 at 1:31am*

**physics**

You hit a 0.2 kg golf ball up at 40o from the horizontal. It travels for 4.86 s and stops on an elevated green 10 m above its initial height traveling down at an angle of 35.4o below the horizontal. What is the total impulse on the golf ball when it hits the ground and stops...
*Saturday, July 27, 2013 at 10:25pm*

**physics**

A spring has a length of 0.190 m when a 0.300 kg mass hangs from it, and a length of 0.750 m when a 2.80 kg mass hangs from it. (a) What is the force constant of the spring? (b) What is the unloaded length of the spring?
*Saturday, July 27, 2013 at 7:20pm*

**Physics**

Q2_2: QUIZ 2, PROBLEM #2 The composite beam AB, of length L=2m, is free at A (x=0) and fixed at B (x=L) and is composed of a round cylindrical core of constant radius R0=1cm bonded inside a sleeve of thickness R0 (outer radius 2R0=2cm). The beam is loaded, as indicated, by a ...
*Saturday, July 27, 2013 at 11:26am*

**physics**

a man walked 32.5m souhward and 78m westward. if it took him 30 minutes to reach his destination.find his average speed?
*Saturday, July 27, 2013 at 9:21am*

**physics**

an automobile travels at a uniform speed of 88 kph. how many metres does it travel in 1 second?
*Saturday, July 27, 2013 at 8:58am*

**Physics**

A 77 kg sprinter is running the 100 m dash. At one instant, early in the race, his acceleration is 4.7 m/s^2. a) What total force does the track surface exert on the sprinter? Assume his acceleration is parallel to the ground. Give your answer as a magnitude. b) What total ...
*Saturday, July 27, 2013 at 12:09am*

**Physics**

When a 81.0 kg. person climbs into an 1400 kg. car, the car's springs compress vertically 1.5 cm. What will be the frequency of vibration when the car hits a bump? (Ignore damping.)
*Friday, July 26, 2013 at 5:35pm*

**physics**

When 1.60 multiplied by 105 J of heat enters a cherry pie initially at 20.0°C, its entropy increases by 470 J/K. What is its final temperature (C)? Drwls answered: delta S = entropy change = 1.6*10^5*[1/293 - 1/T2] = 470 Solve for T2 But after I checked the answer, it is ...
*Friday, July 26, 2013 at 2:14pm*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...
*Friday, July 26, 2013 at 2:09pm*

**physics**

(a) What is the best coefficient of performance for a heat pump that has a hot reservoir temperature of 50.0°C and a cold reservoir temperature of -20.0°C? (b) How much heat in kilocalories would it pump into the warm environment if 3.60 multiplied by 107 J of work (10...
*Friday, July 26, 2013 at 2:09pm*

**physics**

While taking a plane flight to a meeting, a physicist decides to do a mental calculation of how much fuel the plane would consume in the absence of friction, assuming its engines have an efficiency of 22.0% and the mass of the plane is 200,000 kg. Each gallon of jet fuel ...
*Friday, July 26, 2013 at 2:08pm*

Pages: <<Prev | 66 | 67 | 68 | 69 | 70 | 71 | 72 | 73 | **74** | 75 | 76 | 77 | 78 | 79 | 80 | Next>>

Post a New Question | Current Questions