In Bohr’s model, the lowest energy level is called the ground state. The principal quantum number "n" equals 1 for this state. A. The ground state is unstable. The electron eventually spirals into the nucleus, just like in the solar system model. B. The ground state is stable. If no photons are directed at the atom, the electron will just stay in the n=1 orbit. C. The ground state is stable. However, the electron occasionally moves closer to the nucleus, but it quickly returns to n=1

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2

in physics zero. in muscle fatigue could be high

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s