Answer:
W = F * s
Work done equals applied force * distance traveled
Apparent weight = M g (1 - sin θ) since some of applied force will lighten sled
μ = coefficient of kinetic friction
F cos θ = force applied to motion of sled
s = distance traveled
[μ M g (1 - sin θ)] cos θ * s = work done in moving sled
Note that F = μ M g if applied force is in the horizontal direction
6.35x10^-4 OR 6.3x10-4 (if only one decimal number is allowed)
The phrase "light year" is a <u><em>distance</em></u> ... it's the distance that light travels through vacuum in one year.
When you look at an object located 1 light year away from you, you see it as it was 1 year ago.
If a star located 10 light years away from us suddenly brightens, or dims, or explodes, we see the event <em>10 years later.</em>
I<span>n </span>direct current<span> (</span>DC), the electric charge (current<span>) only flows in one direction. Electric charge in </span>alternating current<span> (</span>AC<span>), on the other hand, changes direction periodically. The voltage in </span>AC<span> circuits also periodically reverses because the </span>current<span> changes direction.</span>
