So we want to know what will happen if we put a magnetically soft material in a strong magnetic field. A magnetically soft material is a material whose magnetic field can easily be reversed. Those are ferromagnetic materials. Iron is such a material. When a magnetically soft material is placed into a strong magnetic field it gets its own magnetic field. But its not a permanent magnetic field, it can be changed by a different strong magnetic field.
Hi there!
We can use the rotational equivalent of Newton's Second Law:

Στ = Net Torque (Nm)
I = Moment of inertia (kgm²)
α = Angular acceleration (rad/sec²)
We can plug in the given values to solve.

Answer:
he will use kinetic energy to break through the door
Explanation:
because kinetic energy is movement and force
Answer:
B - Person A's chair rolls backwards.
Explanation:
This can be seen simply through the Conservation of Momentum. When the ball is thrown to be, the ball's momentum(+m) is transfererd to B, so B's chair moves forward(think about it - it makes sense, doesn't it?), meaning A's chair moves backwards.
So, B.
EXTRA TIP: Try drawing a diagram to help you!