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.
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Chapter 8 Solutions
Physics for Scientists and Engineers
- Under 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_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_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_forward
- A 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_forwardA brick has a mass of 1.3kg. It is dropped (from rest) from a height of 18.8m. What is the speed of the brick when it hits the ground? Your Answer: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_forward
- A 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_forwardA skier is sliding downhill at 7 m/s when she reaches an icy patch on which her skis move freely with negligible friction. The difference in altitude between the top of the icy patch and its bottom is 9 m. What is the speed of the skier at the bottom of the icy patch in m/s? Take g = 9.8 m/s2. Round to one decimal place. (hint: do you have to know her mass?)arrow_forwardA 75 kg bicyclist is traveling with some speed. She approaches a hill that is 56 m high. How fast must she be biking to make it to the top of the hill and still be moving 1 m/s?arrow_forward
- A 59.0 kg cheetah accelerates from rest to its top speed of 30.9 m/s. HINT (a) How much net work (in J) is required for the cheetah to reach its top speed? 28166 (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. Cal Need Help? Read It Watch itarrow_forwardA 40 kg stone falls from a height of 10 meters. Accordingly, what is the speed of the stone when it is 5 m above the ground?arrow_forwardHow many times could a 70kg person jump rope with the energy contained in one serving of gummy bears? There are 130 calories per serving of gummy bears. Assume the gummy bear energy is converted completely to potential energy and that each jump is 10.0cm high. Calculate the potential energy per jump using PE = mgh where m is the mass of the person in kilograms, g is the gravitational acceleration constant 9.8m/s^2, and h is the height of each jump in meters. Recall that 1 Joule = 1kgm^2/s^2.arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning