Answer:1. Transparent
2. Transparent
3. Opaque
Explanation: In a transparent medium light can pass through. For opaque objects it does not allow to pass through instead it is reflected back.
<span>The mechanical energy is conserved.
I hope this helps, good luck! :)</span>
Answer:The mass of ball B is 10 kg.
Explanation;
Mass of ball A = 
Velocity of the ball A before collision:
Velocity of ball A after collision=
Mass of ball B= 
Velocity of the ball B before collision:
Velocity of ball B after collision=



The mass of ball B is 10 kg.
The size of the force varies inversely as the square of the distance between the two charges. Therefore, if the distance between the two charges is doubled, the attraction or repulsion becomes weaker, decreasing to one-fourth of the original value.