Answer: (d)
Explanation:
Given
Mass of object 
Speed of object 
Mass of object at rest 
Suppose after collision, speed is v
conserving momentum

Initial kinetic energy

Final kinetic energy

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.
Answer:Negatively charged particle called Free Electrons
Explanation:
Current is the flow of charged particles called Free electrons. Electrons are free to move from one atom to another and we call them a sea of de-localized electrons. In absence of any externally applied emf, these electrons are randomly moving but with the onset of emf, these electrons flow in a particular direction.
B I think. Newtons first law talks about how if some thing is traveling at like 5 mph it’ll stay at 5 mph forever until the force is put on it.
Gravitational potential energy is an object that possesses because of its position in a gravitational field