Answer:
K = 0.076 J
Explanation:
The height of the target, h = 0.860 m
The mass of the steel ball, m = 0.0120 kg
Distance moved, d = 1.50 m
We need to find the kinetic energy (in joules) of the target ball just after it is struck. Let t is the time taken by the ball to reach the ground.

Put all the values,

The velocity of the ball is :

The kinetic energy of the ball is :

So, the required kinetic energy is 0.076 J.
A. Conductors. Because in conductors, gap between valence band and conduction band is negligible. Due to this electrons from valence band moves spontaneously to conduction band and on small heating the conductors.
The correct option is D.
Micheal Friday devised a wire which hanged down into a glass vessel that has a bar magnet secured at the bottom. He then filled the glass vessel with Mercury and connected the apparatus to a battery. This sent electricity through the wire, thus creating a magnetic field around it. This field interacted with the field around the magnet and cause the wire to rotate clock wisely.