Final answer:
The statement regarding parachutes not undergoing negative acceleration is false; parachutes and skydivers do experience negative acceleration when air resistance increases. The acceleration versus time graph for a falling skydiver would decrease to zero as they reach terminal velocity. For further kinematic analysis including velocity after a fall or when forces cease on an icy surface, specific physics equations are applied.
Step-by-step explanation:
The statement 'Parachutes never go through negative acceleration because they float down to the ground slowly' is FALSE. A skydiver, or object, does experience negative acceleration when the force of air resistance opposite to gravity increases as they pick up speed after initially jumping. When the skydiver opens their parachute, there is an immediate increase in air resistance leading to a negative acceleration as they slow down before reaching a constant terminal velocity. At this point, the forces of gravity and air resistance are equal, resulting in zero net force and thus no acceleration; however, this does not mean that the skydiver becomes weightless.
When considering the shape of the graph of the magnitude of the acceleration versus time for a falling skydiver, it starts at 9.81 m/s2 (the acceleration due to gravity), and as they fall, it decreases to zero as they reach terminal velocity.
For a parachutist with a gravitational force of 539 N acting on them, once they open their parachute and experience an air resistance of 615 N, their net acceleration is upwards (thus negative if we define downwards as positive). However, the question about the speed after 10 s cannot be answered without additional information such as initial velocity or time spent at different accelerations.
In the experiment where a ball is launched horizontally from a 2 meter high elevation, the graph of the ball's vertical acceleration versus time would show a constant negative value because gravity is constant and does not change over time (assuming no air resistance).
Considering the kinematic equations, to find the velocity of a skydiver 2.0 s after they jump and before opening their parachute, you would use the equation v = u + at, where u is the initial velocity (zero if starting from rest), a is the acceleration due to gravity, and t is the time elapsed.
Lastly, if a force is applied to accelerate an object on a smooth icy surface and then stops, the object's acceleration becomes zero but maintains its last velocity indefinitely (a, not b, c, or d), assuming zero friction.