A. power plants burn coal. A fossil-fuel power plant is one that burns fossil fuels such as coal, natural gas or petroleum (oil) to produce electricity.
b. Fossil fuels are called so because they have been derived from fossils, which were formed millions of years ago during the time of the dinosaurs. They are fossilized organic remains that over millions of years have been converted to oil, gas, and coal.
C. they are generally classified as non-renewable resources because they take millions of years to form and known viable reserves are being depleted much faster than new ones are generated.
5. a. Gravitational potential energy and work done If an object is lifted, work is done against the force of gravity. When work is done energy is transferred to the object and it gains gravitational potential energy. If the object falls from that height, the same amount of work would have to be done by the force of gravity to bring it back to the Earth’s surface. If an object at a certain height has 2000 J of gravitational potential energy, we can say that: 2000 J of work has been done in getting the object to that height from the ground and 2000 J of work would have to be done to bring it back to the ground.
In 6 secs, the dog covers- S=vt 8.9*6 = 53.4 m. In the same time, the cat covers, 53.4-3.8 = 49.6 m. Thus, speed of the cat, v= s/t, = 49.6/6 = 8.267 m/s
