A boy on a bicycle is resting at the top of a hill. Then, he rides his bicycle
down the hill. Describe how the boy's potential and kinetic energy differ at the
top, middle, and bottom of the hill.

At the top of hill, Potential energy is high and Kinetic energy is almost Zero.

At the middle of hill, Potential energy and Kinetic energy are almost equal.

At the bottom of hill, Potential energy is zero and Kinetic energy is high.

Explanation:

PE = mgh

Where, m =Mass

            g= Acceleration due to gravity

             h = Height

KE = 0.5 mv²

Where, m =Mass

             v = Velocity

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

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.