Answer:
b 1.39 m/s²
Explanation:
Given the following data;
Time = 12 seconds
Distance, S = 100 m
Since it's starting from rest, the initial velocity is equal to 0m/s.
To find the acceleration, we would use the second equation of motion;

Where;
S represents the displacement or height measured in meters.
u represents the initial velocity measured in meters per seconds.
t represents the time measured in seconds.
a represents acceleration measured in meters per seconds square.
Substituting into the equation, we have;
100 = 0(12) + ½*a*12²
100 = 0 + 72
100 = 72a
Acceleration, a = 100/72
Acceleration, a = 1.389 ≈ 1.39 m/s²
I.i = j.j = 1
i.j = j.i = 0
(-2i - 5j)(i -4j)
= (-2i).i + (-2i).(-4j) + (-5j).i + (-5j).(-4j)
= -2 + 0 + 0 + 20 = 18
The formula for calcium oxide is CaO.