If the sack weighs 210 newtons, then an upward force of 210 newtons
exactly cancels the downward force of gravity, and makes the net vertical
force on the bag zero.
ANY upward force that's greater than 210 newtons makes the net force
act upward on the bag, and causes it to accelerate upward.
This is false. Current is the speed of the charge, 1 amp of current is 1 coulomb per second. So you can imagine the current of a circuit as the current of a river. In a parallel circuit, the river breaks into two separate streams. Some of the water goes down one river, some goes down the other. However, the total amount of water/coulombs never changes. This means that some of the total current will go down one river, and one the other. However, with less coulombs now the current will decrease.
Long story short, since there are two paths, the charge will split and depending on the resistance of each parallel stream a different amount of charge will go down each branch.
Its d. the water isn't moving the fish, and that's how they remain stationary. they don't have any currents pushing on them. if this is wrong, its c, which is practically the same thing. but its most likely d.
The block on the action of two forces, the Force of Friction and the Tangential Weight. Using the Newton's Secound Law, we have:
Using the Velocity Hourly Equation, we get:
Uniting the equations:
Entering the unknowns:

Obs: Approximate results
If you notice any mistake in my english, please let me know, because i am not native.