Answer:
2.2nC
Explanation:
Call the amount by which the spring’s unstretched length L,
the amount it stretches while hanging x1
and the amount it stretches while on the table x2.
Combining Hooke’s law with Newton’s second law, given that the stretched spring is not accelerating,
we have mg−kx1 =0, or k = mg /x1 , where k is the spring constant. On the other hand,
applying Coulomb’s law to the second part tells us ke q2/ (L+x2)2 − kx2 = 0 or q2 = kx2(L+x2)2/ke,
where ke is the Coulomb constant. Combining these,
we get q = √(mgx2(L+x2)²/x1ke =2.2nC
The correct answer is A. Most reactive non metals.
Firstly if some one knows how to read the periodic table he would have no confusion in deciding whether group 7 has metals or non metals. Group 7 contains non metals so basically we can easily cancel out two options of metals.
Secondly group 7 non metals are the most reactive non metals as they need only one electron in order to complete their valence shell and become stable.
BCA for sure, b the lines are showing more movement
Here are the 2 reasons:
- Sun damages the eyes
Long-term, unprotected exposure to ultraviolet light from the sun can damage the retina. The retina is the back of the eye, where the rods and cones make visual images, which are then sent to the visual centers in the brain. Damage from exposure to sunlight can also cause the development of cloudy bumps along the edge of the cornea, which can then grow over the cornea and prevent clear vision. UV light is also a factor in the development of cataracts.
- Heat Exhaustion
According to the Centers for Disease Control and Prevention (CDC), heat exhaustion is the body’s response to excessive loss of water and salt, usually through excessive sweating. People working in a hot environment are at risk of heat exhaustion.
