The answer is D. If you aren't consistent with your drop positions, then your data may be invalid. To be frank: it basically screws over the experiment.
Answer:
The sphere is positively charged
Explanation:
This is because when the positively charged rod is brought near the metal rod A, the electrons in metal rod A and sphere B are attracted towards it into metal rod A while the positive charges in the are repelled into sphere B. So, when the charged rod is withdrawn, and metal rod A and sphere B are separated, metal rod A is now negatively charged, but sphere B is positively charged.
So, sphere B is positively charged.
Answer: 7.5 rev/s
Explanation:
We are given the angular velocity 
a helicopter's main rotor blades:
However, we are asked to express this in the International Systrm (SI) units. In this sense, the SI unit for time is second (
):
Answer: Strength of magnet and distance from magnetic material
Explanation:
The potential energy of a magnet is determined by the strength of the magnet and the distance between a magnet and another magnet or a magnetic material. Magnetic materials are materials that would be attracted when brought close to a magnet, example of magnetic materials are most metals.
This question is incomplete because the options are missing; here is the complete question
The ozone layer is found in which layer of the atmosphere?
A. Stratosphere
B. Mesosphere
C. Thermosphere
D. Troposphere
The correct answer is A. Stratosphere
Explanation:
The ozone layer as indicated by its name is mainly composed of Ozone (O2), this layer is essential for life because it filters ultraviolet radiation and acts as a greenhouse effect gas by trapping part of the heat from the sun. Additionally, the ozone layer is located in the stratosphere, which is the second layer of the atmosphere and can be found between 20 km to 50 km from Earth's surface. Moreover, the existence of the ozone layer in the stratosphere makes the temperature increase with height due to the radiation of the sun filter by ozone.
