Physics Physics Practice Problems Solutions Library

# Power Solutions Library

Access 62 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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62 solutions

Power

#### Q. An elite Tour de France cyclist can maintain an output power of 470 W during a sustained climb. At this output power, how long would it take an 88 ...

Solved • Feb 10, 2021

Power

#### Q. If a 4500 Watt oven is on for 4 hours, then how many kilowatt-hours (kWh) of energy are used? 18.0 kWh If the power company charges \$0.10 per kilow...

Solved • Jan 17, 2021

Power

#### Q. The power expended doing 100 J of work in 50 s is _______.

Solved • Nov 2, 2020

Power

#### Q. 1) Four students run up the stairs in the time shown. Rank in order, from largest to smallest, the mechanical work done by each student.2)Four stud...

Solved • Jul 20, 2020

Power

#### Q. A. How many joules of energy does a 100-watt light bulb use per hour? B. How fast would a 70-kg person have to run to have that amount of kinetic e...

Solved • Jul 16, 2020

Power

#### Q. The unit kilowatt-hour is a measure of(a) the rate at which energy is transformed. (b) power.(c) an amount of energy.(d) the amount of power used p...

Solved • Jul 14, 2020

Power

#### Q. The motor of a crane uses power P to lift a steel beam. By what factor must the motor's power increase to lift the beam twice as high in half the t...

Solved • Jul 1, 2020

Power

#### Q. Small birds can migrate over long distances without feeding, storing energy mostly as fat rather than carbohydrate. (Figure 1) Fat is a good form o...

Solved • Jul 1, 2020

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