Not enough information is given to answer this question.
Efficiency is completing a task as fast a possible the the least amount of effort.
The speed is 0.956 m / s.
<u>Explanation</u>:
The kinetic energy is equal to the product of half of an object's mass, and the square of the velocity.
K.E = 1/2
m

where K.E represents the kinetic energy,
m represents the mass,
v represents the velocity.
K.E = 1/2
m

1.10
10^42 = 1/2
3.26
10^31

= (1.10
10^42
2) / (3.26
10^31)
v = 0.956 m / s.
In 2Cr2O7 there’s 2 items; Cr and O
Option 2 is your answer :)