Physics Physics Practice Problems Solutions Library

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Access 54 Power video and text solutions to help you complete your homework. Need to revisit the concept? Watch our Power learn videos.

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54 solutions

Power

Q. 00-gauge copper wire has a diameter of 9.266 mm. Calculate the power loss in a kilometer of such wire when it carries 1.00x102 A

Solved • May 21, 2020

Power

Q. A light-rail commuter train draws 620 A of 700 V DC electricity when accelerating.a) What is its power consumption rate in kilowatts?b)How long doe...

Solved • May 7, 2020

Power

Q. In an average human, basic life processes require energy to be supplied at a steady rate of 100 W.What daily energy intake, in Calories, is require...

Solved • Apr 30, 2020

Power

Q. How much work does an elevator motor do to lift a 1000 kg elevator a height of 100m? answer in J.How much power must the motor supply to do this in...

Solved • Apr 21, 2020

Power

Q. A typical American family uses 1000 kWh of electricity a month.(a) What is the average rms current in the 120 V power line to the house?(b) On aver...

Solved • Mar 10, 2020

Power

Q. A bicyclist of mass 75 kg (including the bicycle) can coast down a 4.0 hill at a steady speed of 12 km/h. Pumping hard, the cyclist can descend the...

Solved • Oct 31, 2018

Power

Q. A 70 kg hiker climbs to the top of a 4300 m -high mountain. The climb is made in 5.5 h starting at an elevation of 2800 m .Calculate the work don...

Solved • Oct 31, 2018

Power

Q. A 1300 kg sports car accelerates from rest to 90 km/h in 7.3 s .What is the average power delivered by the engine?

Solved • Oct 31, 2018

Power

Q. During a workout, football players ran up the stadium stairs in 80 s. The stairs are 83 m long and inclined at an angle of 31 degrees. If a player ...

Solved • Oct 31, 2018

Power

Q. A pump lifts 23.0 kg of water per minute through a height of 3.60 m .What minimum power output rating (watts) must the pump motor have?

Solved • Oct 31, 2018

Power

Q. A ski area claims that its lifts can move 44000 people per hour.If the average lift carries people about 210 m (vertically) higher, estimate the m...

Solved • Oct 31, 2018

Power

Q. A 80 kg skier grips a moving rope that is powered by an engine and is pulled at constant speed to the top of a 23 hill. The skier is pulled a di...

Solved • Oct 31, 2018

Power

Q. A bicyclist coasts down a 6.5 degree hill at a steady speed of 4.5 m/s. Assuming a total mass of 75 kg (bicycle plus rider), what must be the cycli...

Solved • Oct 31, 2018

Power

Q. How long will it take a 1800 W motor to lift a 330 kg piano to a sixth-story window 16.5 m above?

Solved • Oct 31, 2018

Power

Q. An outboard motor for a boat is rated at 65 hp .If it can move a particular boat at a steady speed of 45 km/h , what is the magnitude of the total ...

Solved • Oct 31, 2018

Power

Q. A tandem (two-person) bicycle team must overcome a force of 170 N to maintain a speed of 8.50 m/s .You may want to review (Pages 189 - 191). Fo...

Solved • Oct 31, 2018

Power

Q. Your job is to lift 30-kg crates a vertical distance of 0.90 m from the ground onto the bed of a truck.You may want to review (Pages 189 - 1...

Solved • Oct 31, 2018

Power

Q. A ski tow operates on a slope of angle 15.1 of length 310 m . The rope moves at a speed of 12.1 km/h and provides power for 51 riders at one time...

Solved • Oct 31, 2018

Power

Q. A typical flying insect applies an average force equal to twice its weight during each downward stroke while hovering. Take the mass of the insect ...

Solved • Oct 31, 2018

Power

Q. You may want to review (Pages 189 - 191). For related problemsolving tips and strategies, you may want to view a Video Tutor Solution of A "power...

Solved • Oct 31, 2018

Power

Q. On December 27, 2004, astronomers observed the greatest flash of light ever recorded from outside the solar system. It came from the highly magneti...

Solved • Oct 31, 2018

Power

Q. A pump is required to lift a mass of 810 kg of water per minute from a well of depth 14.1 m and eject it with a speed of 18.1 m/s .How much work ...

Solved • Oct 31, 2018

Power

Q. The Grand Coulee Dam is 1270 m long and 170 m high. The electrical power output from generators at its base is approximately 2010 MW .How many cubi...

Solved • Oct 31, 2018

Power

Q. It is 6.00 km from your home to the physics lab. As part of your physical fitness program, you could run that distance at 10.0 km/hr (which uses up...

Solved • Oct 31, 2018

Power

Q. A 20.0-kg rock is sliding on a rough, horizontal surface at 8.00 m/s and eventually stops due to friction. The coefficient of kinetic friction betw...

Solved • Oct 31, 2018

Power

Q. When its engine of power 76 kW is generating full power, a small single-engine airplane with mass 710 kg gains altitude at a rate of 2.6 m/s .Wha...

Solved • Oct 31, 2018

Power

Q. An elevator has mass 600 kg, not including passengers. The elevator is designed to ascend, at constant speed, a vertical distance of 20.0 m (five f...

Solved • Oct 31, 2018

Power

Q. The hammer of a pile driver weighs 3800 N and must be lifted 2.80 m vertically at constant speed in 4.00 s.What horsepower must the engine provide ...

Solved • Oct 31, 2018

Power

Q. When the 210-kg Genesis Mission capsule crashed with a speed of 311 km/h, it buried itself 81.0 cm deep in the desert floor.Assuming constant acc...

Solved • Oct 31, 2018

Power

Q. The total consumption of electrical energy in the United States is about 1.0 1019 joules per year.What is the average rate of electrical energy con...

Solved • Oct 31, 2018

Power

Q. It is not unusual for a 1000-kg car to get 30 mi/gal when traveling at 60 mi/h on a level road.If this car makes a 200-km trip, how many joules o...

Solved • Oct 31, 2018

Power

Q. For a physics lab experiment, four classmates run up the stairs from the basement to the top floor of their physics building— - a vertical distance...

Solved • Oct 31, 2018

Power

Q. The motor of a crane uses power P to lift a steel beam.By what factor must the motors power increase to lift the beam twice as high in half the time?

Solved • Oct 31, 2018

Power

Q. Six dogs pull a two-person sled with a total mass of 280 kg. The coefficient of kinetic friction between the sled and the snow is 0.080. The...

Solved • Oct 31, 2018

Power

Q. A 95 kg firefighter needs to climb the stairs of a 30-m-tall building while carrying a 45 kg backpack filled with gears.How muc...

Solved • Oct 31, 2018

Power

Q. (a) How much energy is consumed by a 1.2 kW hair dryer used for 12 min?(b) How much energy is consumed by a 11 W night light left on for 18 hr?

Solved • Oct 31, 2018

Power

Q. In a hydroelectric dam, water falls 30.0 m and then spins a turbine to generate electricity. You may want to review (Pages 234 - 238).What is ex...

Solved • Oct 31, 2018

Power

Q. How much work must you do to push a 12.0 kg block of steel across a steel table (μk=0.6) at a steady speed of 1.20 m/s for 5.80 s? What is your pow...

Solved • Oct 31, 2018

Power

Q. At midday, solar energy strikes the earth with an intensity of about 1 kW/m2.What is the area of a solar collector that could collect 150 MJ of en...

Solved • Oct 31, 2018

Power

Q. A 68 kg human sprinter can accelerate from rest to 10 m/s in 3.1 s . During the same time interval, a 31 kg greyhound can go from rest to 20 m/s....

Solved • Oct 31, 2018

Power

Q. When you ride a bicycle at constant speed, nearly all the energy you expend goes into the work you do against the drag force of the air. Model a cy...

Solved • Oct 31, 2018

Power

Q. A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable con...

Solved • Oct 18, 2018

Power

Q. A 3.50-kN piano is lifted by three workers at constant speed to an apartment 25.0 m above the street using a pulley system fastened to the roof of ...

Solved • Oct 18, 2018

Power

Q. For saving energy, bicycling and walking are far more efficient means of transportation than is travel by automobile. For example, when riding at 1...

Solved • Oct 18, 2018

Power

Q. An energy-efficient lightbulb, taking in 28.0 W of power, can produce the same level of brightness as a conventional lightbulb operating at power 1...

Solved • Oct 18, 2018

Power

Q. A certain rain cloud at an altitude of 1.75 km contains 3.20 x 107 kg of water vapor. How long would it take a 2.70-kW pump to raise the same amoun...

Solved • Oct 18, 2018

Power

Q. When an automobile moves with constant speed down a highway, most of the power developed by the engine is used to compensate for the energy transfo...

Solved • Oct 18, 2018

Power

Q. The electric motor of a model train accelerates the train from rest to 0.620 m/s in 21.0 ms. The total mass of the train is 875 g.(a) Find the mini...

Solved • Oct 18, 2018

Power

Q. An 820-N Marine in basic training climbs a 12.0-m vertical rope at a constant speed in 8.00 s. What is his power output?

Solved • Oct 18, 2018

Power

Q. Four students run up the stairs as shown in the figure: Adam (mass of 80 kg) goes up 10 m in 10 s, Bob (80 kg) 10 m in 8 seconds, Claire (64 kg) 10...

Solved • May 23, 2017

Power

Q. A test car of mass 740 kg is moving at a speed of 7.3 m/s when it crashes into a wall to test its bumper. If the car comes to rest in 0.36 s, how m...

Solved • May 16, 2017

Power

Q. A 10 kg object slides along a surface with a coefficient of kinetic friction of 0.3, moving with an initial velocity of 20 m/s. What is the average...

Solved • May 10, 2017

Power

Q. Air resistance at high speed is often given as  Fair = bv2. If the terminal velocity of a 75 kg skydiver is 60 m/s, at what rate is the air resista...

Solved • Feb 21, 2017

Power

Q. A  car moves at a speed of 25 m/s. If the car were to experience 4.5 kN of air resistance at this speed, how much power would the engine need to pr...

Solved • Feb 10, 2017