A child pulls a sled along a rough horizontal surface by applying a constant 20 N force at an angle 60 o above the horizontal. How much work does the child do, in Joules, by pulling the sled 15 meters?

150 J

Explanation:

Work done: This can be defined as the product of force and the horizontal distance moved along the direction of force. The S.I unit of Work is Joules. (J).

The expression for work is given as,

W = Fcos∅y Equation 1

Where W = Work done, F = Force, ∅ = Angle above the horizontal, y = distance.

Given: F = 20 N, ∅ = 60°, y = 15 meters.

Substitute into equation 1

W = 20(cos60)×15

W = 20(0.5)×15

W = 10×15

W = 150 J.

Hence the work done is 150 J.

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.

continuous conducting path for current, power supply