7. A 50 kg pole vaulter running at 10 m/s vaults over the bar. Her speed when she is over the bar is 1.0 m/s. Neglect air resistance, as well as any energy absorbed by the pole, and determine her height as she crosses the bar.

5.1 m

Explanation:

Initial kinetic energy = final kinetic energy + final potential energy

KE = KE + PE

½ mv² = ½ mv² + mgh

½ v² = ½ v² + gh

½ (10 m/s)² = ½ (1.0 m/s)² + (9.8 m/s²) h

h = 5.1 m

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.