Question

Exercise 6: Work output of a large machine in a factory is
89,000 joules, and its input is 102,000 joules. Work
output of a similar machine is 92,000 joules, and its
work input is 104,000 joules. Which machine has greater
efficiency?
Exercise 7: Lucas has been challenged to increase the efficiency of a
device he is redesigning. His goal is 90 percent
efficiency. The work input of the device is fixed at
10 joules, so Lucas is trying to improve work output.
How many joules of work output should Lucas aim for
to attain his goal of 90 percent efficiency?