Answer: I would choose options C and D
Explanation:
Their are two coefficients of friction, static and kinetic, regardless, they have basically the same formula:
u*N = F... aka
coefficient of friction*normal force = force of friction
Hope that helps!
The gravitational pull is weaker.
Answer:
The 1st orbital has no nodes.
Explanation:
A 2s orbital has 1 node and a 1s orbital has no nodes, therefore it is higher in energy than a1s orbital. Also, a 2s orbital is higher in energy because the radius is larger than for a 1s orbital and, therefore, the probability of finding an electron farther from the nucleus is greater in a 2s orbital.