You are correct, the answer is C.
Good insulators are materials that do not allow heat, electricity, light or sound pass through easily. Materials like steel and silver (which are metals) are not good insulators because they make good conductors. They easily allow heat, electricity and the like pass through them.
Thus, the answer is letter C. Rubber.
The ducks' flight path as observed by someone standing on the ground is the sum of the wind velocity and the ducks' velocity relative to the wind:
ducks (relative to wind) + wind (relative to Earth) = ducks (relative to Earth)
or equivalently,

(see the attached graphic)
We have
- ducks (relative to wind) = 7.0 m/s in some direction <em>θ</em> relative to the positive horizontal direction, or

- wind (relative to Earth) = 5.0 m/s due East, or

- ducks (relative to earth) = some speed <em>v</em> due South, or

Then by setting components equal, we have


We only care about the direction for this question, which we get from the first equation:



or approximately 136º or 224º.
Only one of these directions must be correct. Choosing between them is a matter of picking the one that satisfies <em>both</em> equations. We want

which means <em>θ</em> must be between 180º and 360º (since angles in this range have negative sine).
So the ducks must fly (relative to the air) in a direction 224º relative to the positive horizontal direction, or about 44º South of West.
Answer:
(a) 
(b) 
Explanation:
According to Newton's second law:

Recall that the frictional force is related jointly with the coefficient of friction and normal force
. Replacing in the above equation, we get the coefficient of friction:

(a) The coefficient of static friction is related with the force required to set the block in motion:

(b) The coefficient of kinetic friction is related with the force required to keep the block moving with constant speed:

So if the formula for work is force times displacement times cosine(theta), you'd plug in the numbers
100x5 (since there's no angle in the problem, cosine(theta) isn't used
100x5 = 500
So the answer would be B.
Hope that helps!