Acar is driven at constant speed over a circular hill and then into a circular valley with the same radius. at the top of the hill, the normal force on the driver from the car seat is 0. the driver's mass is 77.8 kg. what is the magnitude of the normal force on the driver from the seat when the car passes through the bottom of the valley?

The normal force on the driver at the bottom of the valley is 1,524.9 N.

The given parameters;

The normal force on the driver at the top of the hill will be determined by applying the principle of tensional force on a body at top of a vertical path in a circle;

The normal force on the driver at the bottom of the valley will be determined by applying the principle of tensional force on a body at bottom  of a vertical path in a circle;

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answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.