Terminal velocity balances forces, keeping kinetic energy constant

Steps:

• Constant speed means terminal velocity: drag equals weight, net force zero.
• Kinetic energy Ek = (1/2)mv² remains constant as v is constant.
• Gravitational potential energy Ep = mgh decreases linearly as height h drops at constant rate.
• Graph must show Ek flat and Ep linearly decreasing over time.

Why B is correct:

• Matches constant Ek (terminal velocity) and linearly decreasing Ep (constant descent rate), per energy definitions.

Why the others are wrong:

• A: Shows Ek decreasing, contradicting constant speed.
• C: Shows Ek increasing, implying acceleration not present.
• D: Shows Ep constant, ignoring ongoing descent.

Final answer: B