Answer: Some challenges that I could see would be the walls, possibly a moat, tar, and the towers.
Explanation: The wall is obliviously a main problem, trying to get over it or through it is a difficult challenge. The moat (if it has one) means that there is more than likely only one way to get in or out. If it does have tar it means that the attackers are going to be put in a "sticky situation" And finally the towers, they have people at the top shooting arrows down at you, or throwing things at you.
It would mostly depend on its weight
Answer:
His third law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal and opposite force on object A.
According to Ohm's Law, the resistance, current and voltage are related as:
V = IR
⇒
R = V/I
V is given to be 12 Volts.
I is given to be 0.5 Ampere
So, resistance will be:
R = 12/0.5 = 24 ohms
