Power

Key Questions

• How does power differ from energy?

  Energy is a measure of the capability of doing work (=transform energy) and is measured in Joules. Power is the work per unit time and is measured in Watts (Joules/seconds).

  Consider a pile of bricks. You can take them up to the second floor of a building by hand using energy (you do work transforming chemical energy of your muscles into potential energy of the bricks that are now at the second floor). The same energy is used by a fork lift (it transforms chemical energy in the fuel to do the same as you) BUT it takes 1/10 of the time to do that! The power measures the “efficiency” in terms of time performance in transforming energy doing work.

  Gió · 1 · Apr 12 2015
• What is power?

  Answer:

  Power is the rate at which Work is performed.

  Explanation:

  In general we can write:

  #"Power"="Work"/"time"#

  basically it tells us how "fast" we transfer Energy.
  Consider an example:
  You need to take one truckload of bricks to the third floor of a building.
  You can take the bricks by hand or using a lifting crane; at the end of the day the Work done (against gravity) will be the same in both cases BUT the crane will have done the Work more rapidly than by hand!!!

  Gió · 1 · Mar 25 2018

• What is power?
• How are work and power related?
• How are force and power related?
• How does power affect work?
• How does power differ from energy?
• How does power change with voltage?
• How does power relate to torque?
• How does work relate to conservation of energy?
• How does work relate to gravitational potential energy?
• What is horsepower?
• What is reactive power?
• A cyclist increases his kinetic energy from 11 00 J to 5 200 J in 12 s. How can I calculate his power output during this time?
• A power station burns 80 kilograms of coal per second. Each kg of coal contains 25 million joules of energy. What is the total power of this power station in watts?
• A 1000-watt microwave oven takes 60 seconds to heat a bowl of soup. How many joules of energy does it use?
• It take a clothes dryer 35 minutes to dry a load of towels. If the dryer uses 6,750,000 joules of energy to dry the towels, what is the power rating of the machine?
• A machine uses a force of 200 newtons to do 20,000 joules of work in 20 seconds. Find the distance the object moved and the power of the machine.
• Emily’s vacuum cleaner has a power rating of 200 watts. If the vacuum cleaner does 360,000 joules of work, how long did Emily speed vacuuming?
• Suppose a force of 100 newtons is used to push an object a distance of 5 meters in 15 seconds. Find the work done and the power for this situation
• A wagon is pulled at a speed of 0.40 meters/sec by a horse exerting an 1,800-newton horizontal force. What is the power of this horse?
• A horse moves a sleigh 1.00 kilometer by applying a horizontal 2,000-newton force on its harness for 45 minutes. What is the power of the horse?
• A toaster oven uses 67,500 joules of energy in 45 seconds to toast a piece of bread. What is the power of the oven?
• A hair dryer uses 75,000 joules of energy in 60 seconds. What is the power of this hair dryer?
• A machine does 1,400 joules of work in 30 seconds. What is the power of this machine?
• A force of 30 newtons is applied to a machin e through a distance of 10 meters. The machine is designed to lift an objec t to a height of 2 meters. If the total work output for the machine is 18 newton-meters (N-m), what is the techanical advantage of the machine?
• A force of 200 newtons is applied to a machine in order to lift a 1,000-newton load. What is the mechanical advantage of the machine?
• Question #2c35a
• Question #7bd4e
• What is the power expended when a 17.3 N force pushes a cart 3.9 m in 0.9 seconds?
• A 100-newton object is lifted 100 meters in 100 seconds. What is the power generated in this situation?
• A car requires a constant power of #50# #hp# to maintain a constant velocity of #10# #ms^-1# (about #36# #kmh^-1#). What is the magnitude of the net force impeding motion (friction plus air resistance)?
• If a rocket with a mass of #7 kg# vertically accelerates at a rate of # 3/2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 6 seconds?
• If a rocket with a mass of #700 kg# vertically accelerates at a rate of # 3/2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 4 seconds?
• If a rocket with a mass of #900 kg# vertically accelerates at a rate of # 2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 4 seconds?
• If a rocket with a mass of #900 tons # vertically accelerates at a rate of # 8 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 4 seconds?
• If a rocket with a mass of #900# #"tons"# vertically accelerates at a rate of #3# #ms^-2#, how much power will the rocket have to exert to maintain its acceleration at #4# seconds?
• If a rocket with a mass of #900# #"tons"# vertically accelerates at a rate of #3# #"m/s"^2#, how much power will the rocket have to exert to maintain its acceleration at 2 seconds?
• If a rocket with a mass of #2000 tons # vertically accelerates at a rate of # 3 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 7 seconds?
• If a rocket with a mass of #2000 # tons vertically accelerates at a rate of # 6 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 7 seconds?
• If a rocket with a mass of #2000# #"tons"# vertically accelerates at a rate of #"14 m/s"^2#, how much power will the rocket have to exert to maintain its acceleration at 7 seconds?
• If a rocket with a mass of #2000 tons # vertically accelerates at a rate of # 4 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 7 seconds?
• If a rocket with a mass of #8000 " tons" # vertically accelerates at a rate of # 4 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 3 seconds?
• If a rocket with a mass of #2500# tons vertically accelerates at a rate of # 2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 3 seconds?
• If a rocket with a mass of #2500# tons vertically accelerates at a rate of # 7/3 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 12 seconds?
• If a rocket with a mass of #2500 tons # vertically accelerates at a rate of # 7/3 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 24 seconds?
• If a rocket with a mass of 2500 tons vertically accelerates at a rate of # 7/3 ms^(-2)#, how much power will the rocket have to exert to maintain its acceleration at 5 seconds?
• If a rocket with a mass of #2500 tons # vertically accelerates at a rate of # 5/2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 15 seconds?
• If a rocket with a mass of #3500 tons # vertically accelerates at a rate of # 9/2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 15 seconds?
• If a rocket with a mass of #3500# tons vertically accelerates at a rate of #1/2# #ms^-2#, how much power will the rocket have to exert to maintain its acceleration at 15 seconds?
• If a rocket with a mass of #3500 tons # vertically accelerates at a rate of # 1/2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 7 seconds?
• If a rocket with a mass of #3500# tons vertically accelerates at a rate of # 1/2 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 12 seconds?
• If a rocket with a mass of #3500 "tons"# vertically accelerates at a rate of # 8/5 "m/s"^2#, how much power will the rocket have to exert to maintain its acceleration at 12 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 3/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 12 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 3/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 5 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 1/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 5 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 1/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 9 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 1/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 15 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 1/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 14 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 1/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 6 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 2/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 6 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 2/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 3 seconds?
• If a rocket with a mass of 3500 tons vertically accelerates at a rate of # 2/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 4 seconds?
• If a rocket with a mass of 4000 tons vertically accelerates at a rate of # 4/7 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 4 seconds?
• If a rocket with a mass of 4000 tons vertically accelerates at a rate of # 4/7 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 8 seconds?
• If a rocket with a mass of 4000 tons vertically accelerates at a rate of # 12/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 11 seconds?
• If a rocket with a mass of 4000 tons vertically accelerates at a rate of # 6/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 11 seconds?
• If a rocket with a mass of 4000 tons vertically accelerates at a rate of # 9/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 11 seconds?
• If a rocket with a mass of 2900 tons vertically accelerates at a rate of # 9/5 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 4 seconds?
• If a rocket with a mass of 2900 tons vertically accelerates at a rate of # 4/9 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 4 seconds?
• If a rocket with a mass of 2900 tons vertically accelerates at a rate of # 2/9 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 6 seconds?
• If a rocket with a mass of 2900 tons vertically accelerates at a rate of # 2/9 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 5 seconds?
• If a rocket with a mass of 3900 tons vertically accelerates at a rate of # 7/9 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 5 seconds?
• If a rocket with a mass of 3900 tons vertically accelerates at a rate of # 7/8 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 5 seconds?
• If a rocket with a mass of 3900 tons vertically accelerates at a rate of # 15/8 m/s^2#, how much power will the rocket have to exert to maintain its acceleration at 5 seconds?
• If a #12 kg# object is constantly accelerated from #0m/s# to #60 m/s# over 8 s, how much power musy be applied at #t=3#?
• If a #12 kg# object is constantly accelerated from #0m/s# to #60 m/s# over 8 s, how much power musy be applied at #t=1 #?
• If a #12 kg# object is constantly accelerated from #0m/s# to #40 m/s# over 8 s, how much power musy be applied at #t=1 #?
• If a #12 kg# object is constantly accelerated from #0m/s# to #40 m/s# over 18 s, how much power musy be applied at #t=1 #?
• If a #12 kg# object is constantly accelerated from #0m/s# to #4 m/s# over 7 s, how much power musy be applied at #t=1 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over 6 s, how much power musy be applied at #t=1 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over 6 s, how much power musy be applied at #t=3 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over # 8 s#, how much power musy be applied at #t=3 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over # 8 s#, how much power musy be applied at #t=7#?
• If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over # 9 s#, how much power musy be applied at #t=7#?
• If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over # 9 s#, how much power musy be applied at #t= 6 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #16 m/s# over # 9 s#, how much power musy be applied at #t= 1 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 1 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 3 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 3 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 4 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 5 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 6 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 12s#, how much power musy be applied at #t= 9 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 5 s#, how much power musy be applied at #t= 1 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #18 m/s# over # 5 s#, how much power musy be applied at #t= 2 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #18 m/s# over # 5 s#, how much power musy be applied at #t= 3 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #18 m/s# over # 5 s#, how much power musy be applied at #t= 4 #?
• If a #2 kg# object is constantly accelerated from #0m/s# to #18 m/s# over # 6s#, how much power musy be applied at #t= 4 #?
• If a #2# #kg# object accelerates constantly from #0# #ms^-1# to #15# #ms^-1# over #6# #s#, how much power must be applied at #t=4#?
• If a #2 kg# object is constantly accelerated from #0m/s# to #15 m/s# over # 6s#, how much power musy be applied at #t= 2 #?
• If a #2 kg# object is being constantly accelerated from #0m/s# to #15 m/s# over # 6s#, how much power is being applied at #t= 2 #?
• If a #2 kg# object is being constantly accelerated from #0m/s# to #15 m/s# over # 6s#, how much power is being applied at #t= 3 #?
• If a #2 kg# object is being constantly accelerated from #0m/s# to #15 m/s# over # 6s#, how much power is being applied at #t= 1 #?
• If a #5 kg# object is being constantly accelerated from #0m/s# to #12 m/s# over # 6s#, how much power is being applied at #t= 1 #?
• If a #5 kg# object is being constantly accelerated from #0m/s# to #12 m/s# over # 6s#, how much power is being applied at #t= 3 #?
• If a #5 kg# object is being constantly accelerated from #0m/s# to #12 m/s# over # 16s#, how much power is being applied at #t= 1 s#?
• How much power is needed to accelerate an object with a mass of #12 kg# and a velocity of #5 m/s# at a rate of #2 m/s^2#?
• How much power is needed to accelerate an object with a mass of #4 kg# and a velocity of #7 m/s# at a rate of #5 m/s^2#?
• How much power is needed to accelerate an object with a mass of #4 kg# and a velocity of #3 m/s# at a rate of #6 m/s^2#?
• How much power is needed to accelerate an object with a mass of #4 kg# and a velocity of #8 m/s# at a rate of #6 m/s^2#?
• How much power is needed to accelerate an object with a mass of #4 kg# and a velocity of #8 m/s# at a rate of #2 m/s^2#?
• How much power is needed to accelerate an object with a mass of #5 kg# and a velocity of #3 m/s# at a rate of #2 m/s^2#?
• How much power is needed to accelerate an object with a mass of #5 kg# and a velocity of #3 m/s# at a rate of #12 m/s^2#?
• How much power is needed to accelerate an object with a mass of #5 kg# and a velocity of #3 m/s# at a rate of #9 m/s^2#?
• How much power is needed to accelerate an object with a mass of #6 kg# and a velocity of #3 m/s# at a rate of #9 m/s^2#?
• How much power is needed to accelerate an object with a mass of #6 kg# and a velocity of #3 m/s# at a rate of #7 m/s^2#?
• How much power is needed to accelerate an object with a mass of #6# # kg# and a velocity of #3# # ms^-1# at a rate of #1# # ms^-2#?
• An object with a mass of #5 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #2 #. How much power will it take to accelerate the object at #2 m/s^2?
• An object with a mass of #5 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #2 #. How much power will it take to accelerate the object at #4 m/s^2?
• An object with a mass of #4 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #2 #. How much power will it take to accelerate the object at #4 m/s^2?
• An object with a mass of #4 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #3 #. How much power will it take to accelerate the object at #4 m/s^2?
• An object with a mass of #4 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #3 #. How much power will it take to accelerate the object at #5 m/s^2?
• An object with a mass of #4 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #3 #. How much power will it take to accelerate the object at #4 m/s^2?
• An object with a mass of #4 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #1 #. How much power will it take to accelerate the object at #4 m/s^2?
• An object with a mass of #2 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #1 #. How much power will it take to accelerate the object at #4 m/s^2?
• An object with a mass of #12# #kg# is moving at #9# #ms^-1# over a surface with a kinetic friction coefficient of #1#. How much power will it take to accelerate the object at #4# #ms^-2#?
• An object with a mass of #12 kg# is moving at #9 m/s# over a surface with a kinetic friction coefficient of #1 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #12 kg# is moving at #9 m/s# over a surface with a kinetic friction coefficient of #3 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #2 kg# is moving at #5 m/s# over a surface with a kinetic friction coefficient of #3 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #2 kg# is moving at #5 m/s# over a surface with a kinetic friction coefficient of #3 #. How much power will it take to accelerate the object at #8 m/s^2?
• An object with a mass of #2 kg# is moving at #5 m/s# over a surface with a kinetic friction coefficient of #2 #. How much power will it take to accelerate the object at #8 m/s^2?
• An object with a mass of #2 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #2 #. How much power will it take to accelerate the object at #8 m/s^2?
• An object with a mass of #6 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #2 #. How much power will it take to accelerate the object at #8 m/s^2?
• An object with a mass of #6 kg# is moving at #27 m/s# over a surface with a kinetic friction coefficient of #6 #. How much power will it take to accelerate the object at #8 m/s^2?
• An object with a mass of #8 kg# is moving at #27 m/s# over a surface with a kinetic friction coefficient of #6 #. How much power will it take to accelerate the object at #8 m/s^2?
• An object with a mass of #8 kg# is moving at #7 m/s# over a surface with a kinetic friction coefficient of #6 #. How much power will it take to accelerate the object at #8 m/s^2?
• An object with a mass of #8 kg# is moving at #5 m/s# over a surface with a kinetic friction coefficient of #6 #. How much power will it take to accelerate the object at #18 m/s^2?
• An object with a mass of #8 kg# is moving at #5 m/s# over a surface with a kinetic friction coefficient of #6 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #5 kg# is moving at #5 m/s# over a surface with a kinetic friction coefficient of #6 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #5 kg# is moving at #4 m/s# over a surface with a kinetic friction coefficient of #4 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #5 kg# is moving at #9 m/s# over a surface with a kinetic friction coefficient of #4 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #15 kg# is moving at #9 m/s# over a surface with a kinetic friction coefficient of #4 #. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #15 kg# is moving at #9 m/s# over a surface with a kinetic friction coefficient of #2#. How much power will it take to accelerate the object at #3 m/s^2?
• An object with a mass of #15 kg# is moving at #4 m/s# over a surface with a kinetic friction coefficient of #2#. How much power will it take to accelerate the object at #3 m/s^2?#
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