Answer:
See below ~
Explanation:
The Mechanical Advantage (MA) is defined as the ratio between the force produced by the machine to the force applied to it.
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So,
⇒ 
⇒ This means that the force produced is twice the applied force
Short Answer- Friction
Explanation- There is friction between the grass and the ball. Friction is a type of force that limits motion between two surfaces that are touching. Friction is the force that one surface exerts on another with the two surfaces rubbing together.
This is the answer, hope it helps :)
The plastic rod is made of insulator (plastic), so it does not allow charges moving from one sphere to another. This means that all the electrons given to sphere A will remain on sphere A.
The number of electrons initially given to sphere A is

, and since the charge of 1 electron is

, the net charge left on sphere A after the removal of the rod will be