A lighted candle produces heat however not as much heat as a heater or the sun would.
Answer: A
Explanation: isotopes of the same thing element have the same number of protons in the nucleus but differ in the number of neutrons.
1). The little projectile is affected by friction all the way through the block.
Friction robs some kinetic energy.
2). The block is affected by friction as it scrapes along the top of the post.
Friction robs some kinetic energy.
3). The block is also affected by friction with the air (air resistance) as it
falls to the ground. Friction robs some kinetic energy.
Answer:

Explanation:
Using Newton's second law, we calculate the magnitude of the electric force between the spheres:

The magnitude of the charge in both spheres is the same. So, we calculate the charge, using Coulomb's law:
