A 46-kg uniform disk ( m) sits on the back of a truck traveling at speed m/s when a constant couple moment is applied to it. The disk initially has no angular velocity and the disk does not slip on the truck. Assume the truck bed is long enough to accommodate any subsequent motion of the disk without the disk running out of horizontal surface on which to roll. Find the velocity of the disk's center at the instant 3.3 seconds later if the truck increases its speed to 12 m/s over the same 3.3-s time interval. Consider positive as being to the right. m/s.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.