an amorphous solid is a solid that lacks the long-range order
The answer to this question would be: 1m/s
When you are walking to the north with 2m/s velocity, the stationary object(velocity=0m/s) will look like moving south at 2m/s velocity. That happens because the relative distance between you and the object is reduced by 2m/s in both conditions. In this question, the man seems like have 3m/s velocity. The real velocity should be:
3m/s - 2m/s = 1m/s
Putting a piece of iron or steel inside the coil makes the magnet strong enough to attract objects. The strength of an electromagnet can be increased by increasing the number of loops of wire around the iron core and by increasing the current or voltage.
Sound waves will either be reflected (echo effect) or absorbed (dissipated) depending upon the material make-up of the barrier