<em>A</em> - <em>B</em> = (10<em>i</em> - 2<em>j</em> - 4<em>k</em>) - (<em>i</em> + 7<em>j</em> - <em>k</em>)
<em>A</em> - <em>B</em> = 9<em>i</em> - 9<em>j</em> - 3<em>k</em>
|<em>A</em> - <em>B</em>| = √(9² + (-9)² + (-3)²) = √189 = 3√19
Do it as if you are writing a yes or no statement but have edge more towards the no side.
Answer:
(A) 2.4 N-m
(B) 
(C) 315.426 rad/sec
(D) 1741.13 J
(E) 725.481 rad
Explanation:
We have given mass of the disk m = 4.9 kg
Radius r = 0.12 m, that is distance = 0.12 m
Force F = 20 N
(a) Torque is equal to product of force and distance
So torque
, here F is force and r is distance
So 
(B) Moment of inertia is equal to 
So 
Torque is equal to 
So angular acceleration 
(C) As the disk starts from rest
So initial angular speed 
Time t = 4.6 sec
From first equation of motion we know that 
So 
(D) Kinetic energy is equal to 
(E) From second equation of motion

The initial velocity (its speed before falling off) is approximately 1.95 m/s