Applied Physics (11th Edition)
11th Edition
ISBN: 9780134159386
Author: Dale Ewen, Neill Schurter, Erik Gundersen
Publisher: PEARSON
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Textbook Question
Chapter 8.2, Problem 21P
A motor on an escalator is capable of developing 12 kW of power. (a) How many passengers of mass 75 kg each can it lift a vertical distance of 9.0 m per min. assuming no power loss? (b) What power, in kW, motor is needed to move the same number of passengers at the same rate if 45% of the actual power developed by the motor is lost to friction and heat loss?
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Applied Physics (11th Edition)
Ch. 8.1 - Given: F = 10.0 N s = 3.43 m W = ?Ch. 8.1 - Given: F = 125 N s = 4875 m W = ?Ch. 8.1 - Given: F = 1850 N s = 625 m = 37.5 W = ?Ch. 8.1 - Given: W = 697 ft lb s = 976 ft F = ?Ch. 8.1 - Given: F = 25,700 N s = 238 m W = 5.57 106 J = ?Ch. 8.1 - Given: F = ma m = 16.0 kg a = 9.80 m/s2 s = 13.0 m...Ch. 8.1 - How much work is required for a mechanical hoist...Ch. 8.1 - A hay wagon is used to move bales from the field...Ch. 8.1 - A worker lifts 75 concrete blocks a distance of...Ch. 8.1 - The work required to lift eleven 94.0-lb bags of...
Ch. 8.1 - How much work is done in lifting 450 lb of cement...Ch. 8.1 - How much work is done lifting a 200-kg wrecking...Ch. 8.1 - A gardener pushes a mower a distance of 900 m m in...Ch. 8.1 - A traveler is pulling a suitcase at an angle 40.0...Ch. 8.1 - A crate is pulled 675 ft across a warehouse floor...Ch. 8.1 - A man pulls a sled a distance of 231 m. The rope...Ch. 8.1 - A tractor tows a barge through a canal with a...Ch. 8.1 - Two tractors tow a barge through a canal; each...Ch. 8.1 - Two students push a dune buggy 35.0 m across a...Ch. 8.1 - After a rain, the force necessary to push the dune...Ch. 8.1 - A delivery person carries a 215-N box up stairs...Ch. 8.1 - A crate is pulled by a force of 628 N across the...Ch. 8.1 - A laborer pushes a wheelbarrow weighing 200 N at...Ch. 8.1 - An end loader lifts a 1000-N bucket of gravel 1.75...Ch. 8.2 - Given: W = 132 J t = 7.00 s p = ?Ch. 8.2 - t = 14.3s W = ? Given: P = 75.0 WCh. 8.2 - Given: P = 75.0 W W = 40.0 J t = ?Ch. 8.2 - Given; W = 55.0 J t = 11.0s p = ?Ch. 8.2 - The work required to lift a crate is 310 J. If the...Ch. 8.2 - When a 3600-lb automobile runs out of gas, it is...Ch. 8.2 - An electric golf cart develops 1.25 kW of power...Ch. 8.2 - How many seconds would it take a 7.00-hp motor to...Ch. 8.2 - Prob. 9PCh. 8.2 - A 1500-lb casting is raised 22 0 ft in 2.50 min....Ch. 8.2 - Prob. 11PCh. 8.2 - A wattmeter shows that a motor is drawing 2200 W....Ch. 8.2 - A 525-kg steel beam is raised 30.0 m in 25.0 s....Ch. 8.2 - How long would it take a 4.50-kW motor to raise a...Ch. 8.2 - A 475-kg pre-stressed concrete beam is to be...Ch. 8.2 - A 50.0-kg welder is to be raised 15.0 m in 12.0 s....Ch. 8.2 - An escalator is needed to carry 75 passengers per...Ch. 8.2 - A pump is needed to lift 750 L of water per minute...Ch. 8.2 - A machine is designed to perform a given amount of...Ch. 8.2 - A certain machine is designed to perform a given...Ch. 8.2 - A motor on an escalator is capable of developing...Ch. 8.2 - A pump is capable of developing 4.00 kW of power....Ch. 8.2 - A pallet weighing 575 N is lifted a distance of...Ch. 8.2 - A pallet is loaded with bags of cement; the total...Ch. 8.2 - A bundle of steel reinforcing rods weighing 175 N...Ch. 8.2 - An ironworker carries a 7.50-kg toolbag up a...Ch. 8.3 - Given: m = 11.4 kg g = 9.80m/s2 h = 22.0m Ep = ?Ch. 8.3 - Given: m = 3.50 kg g = 9.80 m/s2 h = 15.0 m Ep = ?Ch. 8.3 - Given: m = 4.70 kg = 9.60 m/s Ek = ?Ch. 8.3 - Given: Ep = 93.6 J g = 9.80m/s2 m = 2.30kg h = ?Ch. 8.3 - A truck with mass 950 siugs is driven 55.0 mi/h....Ch. 8.3 - A bullet with mass 12.0 g travels 415 m/s. Find...Ch. 8.3 - A bicycle and rider together have a mass of 7.40...Ch. 8.3 - A crate of mass 475 kg is raised to a height 17.0...Ch. 8.3 - A tank of water containing 2500 L of water is...Ch. 8.3 - The potential energy of a girder, after being...Ch. 8.3 - A 30.0-g bullet is fired from a gun and possesses...Ch. 8.3 - The Hoover Dam is 726 ft high. Find the potential...Ch. 8.3 - A 250-kg part falls from a plane and hits the...Ch. 8.3 - Prob. 14PCh. 8.3 - Water is pumped at 250 m3/min from a lake into a...Ch. 8.3 - Oil is pumped at 25.0 m3/min into a tank 10.0 m...Ch. 8.3 - Prob. 17PCh. 8.3 - If the kinetic energy of an object is doubled, by...Ch. 8.3 - A 4.20-g slug is shot from a rifle at 965 m/s. (a)...Ch. 8.3 - A window washer with mass 90.0 Kg first climbs...Ch. 8.3 - A painter weighing 630 N climbs to a height of...Ch. 8.4 - A pile driver falls a distance of 2.50 m before...Ch. 8.4 - A sky diver jumps out of a plane at a height of...Ch. 8.4 - A piece of shattered glass falls from the 82nd...Ch. 8.4 - A 10.0-kg mass is dropped from a hot air balloon...Ch. 8.4 - A 0.175-lb ball is thrown upward with an initial...Ch. 8.4 - A pile driver falls a distance of 1.75 m before...Ch. 8.4 - A sandbag is dropped from a hot air balloon at a...Ch. 8.4 - An ironworker drops a hammer 5.25 m to the ground....Ch. 8.4 - A box is dropped 3.60 m to the ground. What is its...Ch. 8.4 - A piece of broken glass with mass 15.0 kg falls...Ch. 8.4 - A ball is thrown downward from the top of a...Ch. 8.4 - Find the maximum height reached by a ball thrown...Ch. 8.4 - A 4,000-kg mass is dropped from a hot air balloon...Ch. 8.4 - A 2.00-kg projectile is fired vertically upward...Ch. 8 - Work is done when a. a force is applied. b. a...Ch. 8 - Power (a) is work divided by time. (b) is measured...Ch. 8 - A large boulder at rest possesses (a) potential...Ch. 8 - A large boulder rolling down a hill possesses (a)...Ch. 8 - With no sir resistance and no friction, a pendulum...Ch. 8 - Can work be done by a moving object on itself?Ch. 8 - Develop the units associated with work from the...Ch. 8 - Is work a vector quantity?Ch. 8 - Is work being done on a boulder by gravity?Ch. 8 - Is work being done by the weight of a grandfather...Ch. 8 - How could the power developed by a man pushing a...Ch. 8 - How does water above a waterfall possess potential...Ch. 8 - What are two devices possessing gravitational...Ch. 8 - Is kinetic energy dependent on time?Ch. 8 - At what point is the kinetic energy of a swinging...Ch. 8 - At what point is the potential energy of a...Ch. 8 - Is either kinetic or potential energy a vector...Ch. 8 - Can an object possess both kinetic and potential...Ch. 8 - Why is a person more likely to be severely injured...Ch. 8 - How many joules are in one kilowatt-hour?Ch. 8 - An endloader holds 1500 kg of sand 2.00 m off the...Ch. 8 - How high can a 10.0-Kg mass be lifted by 1000 J of...Ch. 8 - A 40.0-kg pack is carried up a 2500-m-high...Ch. 8 - Find the average power output in Problem 4 in (a)...Ch. 8 - A 10.0-kg mass lias a potential energy of 10.0 J...Ch. 8 - A 10.0-lb weight has a potential energy of 20.0 ft...Ch. 8 - At what speed does a 1.00-kg mass have a kinetic...Ch. 8 - At what speed does a 10.0-N weight have a kinetic...Ch. 8 - What is the kinetic energy of a 3000-lb automobile...Ch. 8 - What is the potential energy of an 80.0-kg diver...Ch. 8 - What is the kinetic energy of a 0.020-kg bullet...Ch. 8 - What is the potential energy of an 85.o-kg high...Ch. 8 - A worker pulls a crate 10.0 m by exerting a force...Ch. 8 - A hammer falls from a scaffold on a building 50.0...Ch. 8 - Rosita needs to purchase a sump pump for her...Ch. 8 - A roller coaster designer must carefully balance...Ch. 8 - A 22,500-kg Navy fighter jet flying 235 km/h must...Ch. 8 - The hydroelectric plant at the Itaipu Dam, located...Ch. 8 - A 1250-kg wrecking ball is lifted to a height of...
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