What is the solution?

1) x = 30 - 8 t

2) x = -10

3) x = -10 + 5 t

4) x = -10 - 4 t

Explanation:

Motion 1:  constant negative velocity calculated via the points (0, 30) and (5, -10) rendering the equation of motion  x = 30 - 8 t

Motion 2: constant position over time, so the object is not moving, and the equation of motion is x = -10

Motion 3: constant positive velocity estimated via the points (0, -10) and (2, 0), and the equation of motion is:  x = -10 + 5 t

Motion 4: constant negative velocity estimated via the points (0, -10) and (5, -30), and the equation of motion is:  x = -10 - 4 t

The starting position of motion 1 is 30 meters

the starting position for the other 3 motions is - 10 meters. And none of them is accelerated (acceleration = zero for all).

powerful computers now, not then

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.