Answer:
The body acts under the influence of gravity.
Explanation:
An object experiencing free fall is acting under the influence of gravitational force and the acceleration due gravity is positive for any falling object. The body is able to fall freely due to the effect of gravity on it. This gravity effect causes the body to get attracted to the earth's gravitational surface due to gravitational pull exerted on the body.
Just because the book is moving doesn't tell you anything about the forces on it, or even whether there ARE any.
Just look at Newton's first law of motion, and this time, let's try and THINK about it too. It says something to the effect that any object continues in constant, uniform MOTION ..... UNLESS acted on by an external force.
Answer:
C. Mantle
Explanation:
The Mantle is a thick layer of solid and partially melted rock
Answer:
More than enough solar energy (8.2 million quad BTUs, 1 quad = 2.9 x1011 kWh) hits Earth's surface each year to meet all of societies' needs. Currently we use about 400 quads per year to run our society. Good building design allows passive use of sunlight to heat homes. Simple solar collectors are used to heat water and cook food. As useful as it is for these purposes, thermal energy from sunlight is still a low quality energy compared to electricity. Computers, most machinery, light bulbs, subway trains, and much more all require electricity. It is possible to turn thermal energy from the sun into electricity. In this unit we will examine how.
. We will also examine how to make electricity directly from light using the photovoltaic cells.
