One possibility for a low-pollution automobile is for it to use energy stored in a heavy rotating flywheel. Suppose such a car has a total mass of 1100 kg, uses a uniform cylindrical flywheel of diameter 1.50 m and mass 240 kg, and should be able to travel 350 km without needing a flywheel “spinup.” ( a ) Make reasonable assumptions (average frictional retarding force = 450 N, twenty acceleration periods from rest to 95 km/h, equal uphill and downhill, and that energy can be put back into the flywheel as the car goes downhill), and estimate what total energy needs to be stored in the flywheel. ( b ) What is the angular velocity of the flywheel when it has a full “energy charge”? ( c ) About how long would it take a 150-hp motor to give the flywheel a full energy charge before a trip?
One possibility for a low-pollution automobile is for it to use energy stored in a heavy rotating flywheel. Suppose such a car has a total mass of 1100 kg, uses a uniform cylindrical flywheel of diameter 1.50 m and mass 240 kg, and should be able to travel 350 km without needing a flywheel “spinup.” ( a ) Make reasonable assumptions (average frictional retarding force = 450 N, twenty acceleration periods from rest to 95 km/h, equal uphill and downhill, and that energy can be put back into the flywheel as the car goes downhill), and estimate what total energy needs to be stored in the flywheel. ( b ) What is the angular velocity of the flywheel when it has a full “energy charge”? ( c ) About how long would it take a 150-hp motor to give the flywheel a full energy charge before a trip?
One possibility for a low-pollution automobile is for it to use energy stored in a heavy rotating flywheel. Suppose such a car has a total mass of 1100 kg, uses a uniform cylindrical flywheel of diameter 1.50 m and mass 240 kg, and should be able to travel 350 km without needing a flywheel “spinup.” (a) Make reasonable assumptions (average frictional retarding force = 450 N, twenty acceleration periods from rest to 95 km/h, equal uphill and downhill, and that energy can be put back into the flywheel as the car goes downhill), and estimate what total energy needs to be stored in the flywheel. (b) What is the angular velocity of the flywheel when it has a full “energy charge”? (c) About how long would it take a 150-hp motor to give the flywheel a full energy charge before a trip?
Study of body parts and their functions. In this combined field of study, anatomy refers to studying the body structure of organisms, whereas physiology refers to their function.
Some European trucks run on energy stored in a rotating flywheel, with an electric motor getting the flywheel up to its top speed of
250 Trad/s. One such flywheel is a solid, uniform cylinder with a mass of 730 kg and a radius of 0.972 m. (a) What is the kinetic energy
of the flywheel after charging? (b) If the truck uses an average power of 7.8 kW, for how many minutes can it operate between
chargings?
(a) Number
(b) Number
Units
Units
A cyclist intends to cycle up a 8 degrees hill whose vertical height is 175 m. If each complete
revolution of the pedals moves the bike 5.5 m along its path, calculate the average force that must
be exerted on the pedals tangent to their circular path. Neglect work done by friction and other
losses. The pedals turn in a circle of diameter 30 cm. The total mass of the cyclist and their bike is
110 kg.
Trucks can be run on energy stored in a rotating flywheel, with an electric motor getting the flywheel up to its top speed of 200p rad/s. Suppose that one such flywheel is a solid, uniform cylinder with a mass of 500 kg and a radius of 1.0 m. (a) What is the kinetic energy of the flywheel after charging? (b) If the truck uses an average power of 8.0 kW, for how many minutes can it operate between chargings?
Chapter 10 Solutions
Physics for Scientists and Engineers with Modern Physics
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.