Final answer:
A 65 kg skydiver's mass and weight remain constant, while his velocity increases until reaching terminal velocity. Terminal velocity occurs when air resistance equals the force of gravity. Factors like altitude, position, and frontal area affect terminal velocities, with the specific values calculated using physics equations.
Step-by-step explanation:
When a 65 kg skydiver jumps from a plane, his mass remains constant (a), his velocity increases due to the acceleration of gravity until it reaches terminal velocity (b), his acceleration is not zero initially as he accelerates due to gravity, but it approaches zero as he reaches terminal velocity (c), and his weight remains constant as it is a measure of the force of gravity on his mass (d). True or False: A skydiver initially accelerates in his jump. This is true; a skydiver does accelerate due to gravity until reaching a state of constant velocity known as terminal velocity. This does not mean the skydiver becomes weightless, but instead, the net acceleration becomes zero when the force of air resistance equals the force of gravity.
Skydivers are affected by both acceleration due to gravity and air resistance. The graph of the magnitude of the acceleration versus time would show an initial high value that decreases over time as the skydiver accelerates, until it levels off near zero when terminal velocity is reached. The shape of the graph would start steep and then curve downwards, flattening as terminal velocity is achieved.
To calculate terminal velocities for skydivers of different masses in various positions, assumptions about their frontal areas are necessary. For example, a 75 kg skydiver achieves a terminal velocity of about 350 km/h when in a headfirst position and about 200 km/h in a spread-eagle position due to increased drag. The time it would take to reach the ground depends on factors like altitude and whether they reach terminal velocity quickly, but can be calculated using the appropriate physics equations, considering acceleration due to gravity and resistance offered by air.