12. A plastic ruler is rubbed on a cotton shirt. The ruler gains a positive charge. Which of the following statements is true?
A. Protons jumped ON TO the ruler from the shirt.
B. Protons jumped OFF OF the ruler and on to the shirt.
C. Electrons jumped ON TO the ruler from the shirt.
D. Electrons jumped OFF OF the ruler and on to the shirt.

12000j is work done

its c i just checked it

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