Answer:
They do this because it covers the whole surface which they are cleaning. the cleaner all hold the same charge and repel from each other and cover the whole surface. They want to do this to make sure the item that they cleaning is clean.
Answer:
Explanation:
Given
radius of path 
Velocity of Particle 
where t=time in seconds
angular velocity of particle is given by


And angular acceleration is given by


tangential acceleration is 

Centripetal acceleration 

net acceleration is sum of tangential and centripetal force at any time t is given by



Answer:
B. holding a coffee mug
Explanation:
Something must move a distance for work to be done.
Answer:

Explanation:
Capacitance C is given by

A= area of capacitor cross section
d= distance
therefore,

A_1= πR^2
d_1= d

A_= π(2R)^2
d_2 = 2d

threfore

and

also we know that E= V/d
⇒
⇒
= A_1/A_2=
=4
therefore,
