A hard rubber plastic comb is made out of rubber so it doesn't conduct electricity. This means that it is an insulator. Unlike a conductor (a metal comb), an insulator keeps the electrons at the place of where it was rubbed instead of equally distributing them around the surface of the comb.
In a metal comb, the charges within the comb move around while in the rubber comb they can't move around because in an insulator, it doesn't allow the movement of charges.
B dropping a ball
C tentative and testable
The displacement should be a negative value. since your zero point is where you dropped it. The answer is C
Answer:![\vec{v_R}=\hat{i}[-329.11]+\hat{j}[516.18]](https://tex.z-dn.net/?f=%5Cvec%7Bv_R%7D%3D%5Chat%7Bi%7D%5B-329.11%5D%2B%5Chat%7Bj%7D%5B516.18%5D)
Explanation:
Given
Plane is initially flying with velocity of magnitude 
at angle of 
with North towards west
Velocity of plane airplane can be written as
Now wind is encountered with speed of 
at angle of 
resultant velocity
![\vec{v_R}=\hat{i}[-385.67+56.56]+\hat{j}[459.62+56.56]](https://tex.z-dn.net/?f=%5Cvec%7Bv_R%7D%3D%5Chat%7Bi%7D%5B-385.67%2B56.56%5D%2B%5Chat%7Bj%7D%5B459.62%2B56.56%5D)
for direction 
west of North
Answer:
C. 233 km/h
Explanation:
Ground speed = air speed + wind speed
250 km/h = v + 17 km/h
v = 233 km/h
