Objects repel and attract because of a thing called electrostatic attraction. When objects have the same charge (positive or negative), then they will repel, and if they have opposite charges then they will attract
Answer:
The potential difference between the ends of a wire is 60 volts.
Explanation:
It is given that,
Resistance, R = 5 ohms
Charge, q = 720 C
Time, t = 1 min = 60 s
We know that the charge flowing per unit charge is called current in the circuit. It is given by :
I = 12 A
Let V is the potential difference between the ends of a wire. It can be calculated using Ohm's law as :
V = IR
V = 60 Volts
So, the potential difference between the ends of a wire is 60 volts. Hence, this is the required solution.
This question is poorly stated, but I assume you mean what conditions are needed. It would have to be cold outside, correct?
Answer:
If F is a constant, we can take f = 1
f = m×a
ma = 1
therefore we can say that force is hence proportinal to the product of mass and acceleration.
The force exerted by the magnetic in terms of the magnetic field is,

Where B is the magnetic fied strength and F is the force.
Thus, if the magnetic A has twice magnetic field strength than the magnet B,
Then,

Thus, the force exerted by the magnet B is,

Thus, the force exerted by the magnet B on magnet A is 50 N.
The force exerted by the magnet A exerts on the magnet B is exactly 100 N as given.
Hence, the option B is the correct answer.