Principles of Physics: A Calculus-Based Text, Hybrid (with Enhanced WebAssign Printed Access Card)
5th Edition
ISBN: 9781305586871
Author: Raymond A. Serway, John W. Jewett
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Videos
Question
Chapter 7, Problem 38P
(a)
To determine
To determine: The number of times must the student run the flight of stairs to lose
(b)
To determine
To determine: The average power output in Watt and in horsepower, as he runs up the stairs.
(c)
To determine
To determine: Whether this activity in itself a practical way to lose weight.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
In an attempt to conserve energy (and, let’s be honest, save some cash), Bob decides to ride his bike to work every day. He starts out by riding a half mile uphill, which slows him down by 4 miles per hour. The rest of the ride is a mile downhill, which speeds him up by 5 miles per hour. After several days, he notices that when he reaches the top of the hill, he’s exactly halfway there if you measure in terms of time. How fast would Bob be riding if the trip were on level ground?
To enter the main pool at an amusement part, a swimmer uses a water slide which has a vertical height of 2.83 m. Find her speed at the bottom of the slide if she starts with an initial speed of 0.750 m/s.
Under normal conditions the human heart converts about 12.5J of chemical energy per second into 1.25 W of mechanical power as it pumps blood throughout the body.
HINT
(a) Determine the number of Calories required to power the heart for one day, given that 1 Calorie equals 4186 J.
Cal
(b) Metabolizing 1 kg of fat can release about 9000 Calories of energy. What mass of metabolized fat (in kg) would power the heart for one day?
kg
Need Help?
Watch It
Read It
Chapter 7 Solutions
Principles of Physics: A Calculus-Based Text, Hybrid (with Enhanced WebAssign Printed Access Card)
Ch. 7.1 - By what transfer mechanisms does energy enter and...Ch. 7.1 - Consider a block sliding over a horizontal surface...Ch. 7.2 - Prob. 7.3QQCh. 7.2 - Prob. 7.4QQCh. 7.4 - Prob. 7.5QQCh. 7 - You hold a slingshot at arms length, pull the...Ch. 7 - An athlete jumping vertically on a trampoline...Ch. 7 - Prob. 3OQCh. 7 - Two children stand on a platform at the top of a...Ch. 7 - Answer yes or no to each of the following...
Ch. 7 - A ball of clay falls freely to the hard floor. It...Ch. 7 - What average power is generated by a 70.0-kg...Ch. 7 - In a laboratory model of cars skidding to a stop,...Ch. 7 - At the bottom of an air track tilted at angle , a...Ch. 7 - One person drops a ball from the top of a building...Ch. 7 - Prob. 2CQCh. 7 - Does everything have energy? Give the reasoning...Ch. 7 - Prob. 4CQCh. 7 - Prob. 5CQCh. 7 - Prob. 6CQCh. 7 - A block is connected to a spring that is suspended...Ch. 7 - Consider the energy transfers and transformations...Ch. 7 - Prob. 9CQCh. 7 - Prob. 10CQCh. 7 - Prob. 1PCh. 7 - Prob. 2PCh. 7 - Review. A bead slides without friction around a...Ch. 7 - At 11:00 a.m, on September 7, 2001, more than one...Ch. 7 - A block of mass 0.250 kg is placed on top of a...Ch. 7 - A block of mass m = 5.00 kg is released from point...Ch. 7 - Two objects are connected by a light string...Ch. 7 - Prob. 8PCh. 7 - Prob. 9PCh. 7 - Prob. 10PCh. 7 - Prob. 11PCh. 7 - A crate of mass 10.0 kg is pulled up a rough...Ch. 7 - Prob. 13PCh. 7 - Prob. 14PCh. 7 - A block of mass m = 2.00 kg is attached to a...Ch. 7 - Prob. 16PCh. 7 - A smooth circular hoop with a radius of 0.500 m is...Ch. 7 - Prob. 18PCh. 7 - Prob. 19PCh. 7 - As shown in Figure P7.20, a green bead of mass 25...Ch. 7 - A 5.00-kg block is set into motion up an inclined...Ch. 7 - The coefficient of friction between the block of...Ch. 7 - Prob. 23PCh. 7 - Prob. 24PCh. 7 - Prob. 25PCh. 7 - Prob. 26PCh. 7 - A child of mass m starts from rest and slides...Ch. 7 - The electric motor of a model train accelerates...Ch. 7 - Prob. 29PCh. 7 - Prob. 30PCh. 7 - Prob. 31PCh. 7 - Sewage at a certain pumping station is raised...Ch. 7 - Prob. 33PCh. 7 - Prob. 34PCh. 7 - Prob. 35PCh. 7 - Prob. 36PCh. 7 - Prob. 37PCh. 7 - Prob. 38PCh. 7 - Prob. 39PCh. 7 - Prob. 40PCh. 7 - A loaded ore car has a mass of 950 kg and rolls on...Ch. 7 - Prob. 42PCh. 7 - A certain automobile engine delivers 2.24 104 W...Ch. 7 - Prob. 44PCh. 7 - A small block of mass m = 200 g is released from...Ch. 7 - Prob. 46PCh. 7 - Prob. 47PCh. 7 - Prob. 48PCh. 7 - Prob. 49PCh. 7 - Prob. 50PCh. 7 - Prob. 51PCh. 7 - Prob. 52PCh. 7 - Jonathan is riding a bicycle and encounters a hill...Ch. 7 - Prob. 54PCh. 7 - A horizontal spring attached to a wall has a force...Ch. 7 - Prob. 56PCh. 7 - Prob. 57PCh. 7 - Prob. 58PCh. 7 - Prob. 59PCh. 7 - Prob. 60PCh. 7 - Prob. 61PCh. 7 - Prob. 62PCh. 7 - Make an order-of-magnitude estimate of your power...Ch. 7 - Prob. 64PCh. 7 - Prob. 65PCh. 7 - Review. As a prank, someone has balanced a pumpkin...Ch. 7 - Review. The mass of a car is 1 500 kg. The shape...Ch. 7 - A 1.00-kg object slides to the right on a surface...Ch. 7 - A childs pogo stick (Fig. P7.69) stores energy in...Ch. 7 - Prob. 70PCh. 7 - Prob. 71PCh. 7 - Prob. 72PCh. 7 - A block of mass m1 = 20.0 kg is connected to a...Ch. 7 - Prob. 74PCh. 7 - Prob. 75PCh. 7 - Prob. 76PCh. 7 - Prob. 77PCh. 7 - Prob. 78PCh. 7 - A block of mass 0.500 kg is pushed against a...Ch. 7 - A pendulum, comprising a light string of length L...Ch. 7 - Jane, whose mass is 50.0 kg, needs to swing across...Ch. 7 - A roller-coaster car shown in Figure P7.82 is...Ch. 7 - Prob. 83P
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- The Viper roller coaster at Great America starts at a height of 30 m with a velocity of 3 m/sec. A) How fast is the car going when it reaches the ground after that first hill? B) A later hill is only 10 m high. How fast is the car going when it gets to the top of the second hill? Assume there is no friction on the track.arrow_forwardEnergy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is 1 kilocalorie, which we define as 1 kcal=4 186 J. Metabolizing 1 gram of fat can release 9.00 kcal. A student decides to try to lose weight by exercising. She plans to run up and down the stairs in a football stadium as fast as she can and as many times as necessary. Is this a practical way to lose weight? To evaluate the program, suppose she runs up a flight of 100 steps, each 0.20 m high, in 45.0 s. For simplicity, ignore the energy she uses in coming down (which is small). Assume that a typical efficiency for human muscles is 20.0%. This means that when your body converts 100 J from metabolizing fat, 20 J goes into doing mechanical work (here, climbing stairs). The remainder goes into internal energy. Assume the student's mass is 65.0 kg. (a) How many times must she run the flight of stairs to lose 1 pound of fat? (b) What is her average power output, in watts and in horsepower, as she is…arrow_forwardUnder normal conditions the human heart converts about 13.2 J of chemical energy per second into 1.32 W of mechanical power as it pumps blood throughout the body. HINT (a) Determine the number of Calories required to power the heart for one day, given that 1 Calorie equals 4186 J. Cal (b) Metabolizing 1 kg of fat can release about 9000 Calories of energy. What mass of metabolized fat (in kg) would power the heart for one day? kgarrow_forward
- An athlete jumps over a barrier with an initial speed of 2.2 m/s. How much will the athlete be raised during the jump?arrow_forwardA race car with a mass of 1850 kg accelerates from rest down a race track at a rate of 21.0 m/s2. If the track is 400m long, what is the gain in kinetic energy of the car when it reaches the end of the track?arrow_forwardYou are driving to work at 60 mph and need to accelerate to 75 mph. How long will it take to reach this speed? Express this quantity in units of seconds. Assume the engine is rated at 140 hp and is 25% efficient. The combined vehicle and driver mass is 2970 lbm.arrow_forward
- What is the kinetic energy of 1 kg of air (about 1 m3) moving at 15 m/s (about 32 mph)? If it takes 2 seconds to raise an 8 kg block a vertical height of 1 m, what is the power expended?arrow_forwardUnder normal conditions the human heart converts about 13.5 J of chemical energy per second into 1.35 W of mechanical power as it pumps blood throughout the body. (a) Determine the number of Calories required to power the heart for one day, given that 1 Calorie equals 4186 J. ______________ Cal (b) Metabolizing 1 kg of fat can release about 9000 Calories of energy. What mass of metabolized fat (in kg) would power the heart for one day? ________________kgarrow_forwardA typical human brain has a mass of 1.4 kg, which makes up about 2% of a person's mass. However, the brain requires 20% of the body's power consumption. In essence, the brain requires 10 times as much power as any other organ in the body. The average power output of the human brain is about 2.0 × 10¹ W. Assume that the brain's power output could be converted into mechanical work and calculate how high we could use this power to lift an apple (m = 0.20 kg) in one minute. Number pa Unitsarrow_forward
- Energy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is one kilocalorie, defined as 1 kcal = 4 186 J. Metabolizing 1 g of fat can release 9.00 kcal. A student decides to try to lose weight by exercising. He plans to run up and down the stairs in a football stadium as fast as he can and as many times as necessary. To evaluate the program, suppose he runs up a flight of 80 steps, each 0.150 m high, in 65.0 s. For simplicity, ignore the energy he uses in coming down (which is small). Assume a typical efficiency for human muscles is 20.0%. This statement means that when your body converts 100 J from metabolizing fat, 20 J goes into doing mechanical work (here, climbing stairs). The remainder goes into extra internal energy. Assume the student’s mass is 75.0 kg. (a) How many times must the student run the flight of stairs to lose 1.00 kg of fat? (b) What is his average power output, in watts and in horsepower, as he runs up the stairs? (c) Is this…arrow_forwardA 50.0 kg cheetah accelerates from rest to its top speed of 30.3 m/s. (a) How much net work (in J) is required for the cheetah to reach its top speed? (b) One food Calorie equals 4186 J. How many Calories of net work are required for the cheetah to reach its top speed? Note: Due to inefficiencies in converting chemical energy to mechanical energy, the amount calculated here is only a fraction of the energy that must be produced by the cheetah's body.arrow_forwardA typical human brain has a mass of 1.4 kg, which makes up about 2% of a person's mass. However, the brain requires 20% of the body's power consumption. In essence, the brain requires 10 times as much power as any other organ in the body. The average power output of the human brain is about 2.0*10^1 W. Assume that the brain's power output could be converted into mechanical work and calculate how high we could use this power to lift an apple (m=0.20kg) in one minute.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
8.01x - Lect 11 - Work, Kinetic & Potential Energy, Gravitation, Conservative Forces; Author: Lectures by Walter Lewin. They will make you ♥ Physics.;https://www.youtube.com/watch?v=9gUdDM6LZGo;License: Standard YouTube License, CC-BY