Author Question: A 1200 W toaster does enough work in 10 seconds to raise an 80 kg man to a height of 15 meters. ... (Read 81 times)

jazziefee · **on:** Jul 28, 2018

A 1200 W toaster does enough work in 10 seconds to raise an 80 kg man to a height of 15 meters.

What will be an ideal response?

Question 2

Heat exchangers are important. Explain their use in power plants, including large scale solar power plants.

What will be an ideal response?

stano32 · **Reply #1 on:** Jul 28, 2018

Answer to Question 1

To raise an 80 kg man 15 meters takes 80 kg x 10 m/s2 x 15 m = 12,000 J of
work. In 10 s the 1200 W toaster does 1200 W x 10 s = 12.000 J of work. These are the
same, so the statement is true.

Answer to Question 2

The working fluid of the power plant may be water or some other fluid. At the
final stage, the working fluid is usually water or steam that turns the turbine blades. Many
power plants use working fluids at high pressure (as, for example, nuclear pressurized water
reactors or solar towers). In order to get from the high-pressure working fluid to water or
steam, at least one heat exchanger is necessary.