Answer   how does using a ramp make work easier when loading a piano onto a truck three feet above the ground? a. it allows a larger force to be applied over a shorter distance. b. it allows a larger force to be applied over a longer distance. c. it allows a smaller force to be applied over a shorter distance. d. it allows a smaller force to be applied over a longer distance.

Here when we use ramp to move an object to some height the applied force to pull it upwards is less

As we know that when we pull an object directly upwards then the applied force must be equal to the weight of the object

so here applied force is

F = mg

If we pull the object on the inclined plane then the applied force is parallel to the inclined plane

This force is is given by

so here we will have if we compare the two force we can say that force on the object to move it upwards will be less if we pull it along the inclined plane.

But here since we have to pull it over the inclined plane which would be longer in length then we pull it directly upwards

So correct answer would be

D. It allows a smaller force to be applied over a longer distance.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

so here is the information for current research:

-nrel's geothermal analysts, scientists, and engineers perform a full range of research from developing advanced methods of locating and accessing geothermal resources to exploring innovative technologies to extract and produce clean energy from the heat of the earth

and here is the information for the technology of geothermal energy:

-it's clean and sustainable

-resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma

-almost everywhere, the shallow ground or upper 10 feet of the earth's surface maintains a nearly constant temperature between 50° and 60°f (10° and 16°c)

-geothermal heat pumps can tap into this resource to heat and cool buildings

-a geothermal heat pump system consists of a heat pump, an air delivery system (ductwork), and a heat exchanger-a system of pipes buried in the shallow ground near the building

-in the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system

-in the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger

-the heat removed from the indoor air during the summer can also be used to provide a free source of hot water