I think its A as in density
Answer: One thing magnetism and electricity have in common is that they are related.
Explanation: Flowing electrons produce a magnetic field, and spinning magnets cause an electric current to flow.
Answer: For number 9, the children would not be able to close the box.
Explanation: The combined force of the children is 55 N. The box spring overpowers them with 60 N. I hope this helps!
Answer:
The altitude of geostationary satellite is 
Explanation:
Given that,
Radius of moon's orbit 
Time period 
We need to calculate the orbital radius of geostationary satellite is
Using formula of time period


Where, G = gravitational constant
M = Mass of earth
T = time period of geostationary satellite orbit
Put the value in to the formula


We need to calculate the altitude of geostationary satellite
Using formula of altitude

Where, R = radius of earth
a = radius of geostationary satellite
Put the value into the formula



Hence, The altitude of geostationary satellite is 
Answer:
Voltage-gated K+ channels