A skydiver is subject to two forces: gravity and air resistance. Falling vertically, she reaches a constant terminal speed at some time after jumping from the plane. Since she is moving at a constant velocity from that time until her chute opens, we conclude from the work kinetic energy theorem that, over that time interval,
A. The work done by gravity equals the negative of the work done by the air resistance.
B. The work done by gravity is zero.
C. The work done by gravity equals the work done by air resistance.
D. The work done by air resistance is 0.
E. Her kinetic energy increases.
Please help me with this...
before opening her chute, what force of air resistance will she encounter when she reaches terminal velocity
To determine the answer to this question, let's break it down step by step:
1. The skydiver is subject to two forces: gravity and air resistance.
2. As she falls vertically, there are two important factors we need to consider: gravity and air resistance.
3. Gravity is a downward force that pulls the skydiver towards the ground.
4. Air resistance is a force that opposes the motion of the skydiver as she falls.
5. As the skydiver falls, the force of gravity initially exceeds the force of air resistance. As a result, she accelerates.
6. Eventually, the force of air resistance increases until it equals the force of gravity. At this point, the skydiver reaches what is called "terminal velocity" - a constant velocity at which the net force on her is zero.
7. Now, let's analyze the options provided:
A. The work done by gravity equals the negative of the work done by the air resistance.
This option suggests that the work done by gravity and air resistance are equal in magnitude but have opposite signs. However, this is incorrect. At terminal velocity, the net force is zero, which means no work is being done by either gravity or air resistance.
B. The work done by gravity is zero.
This option is correct. At terminal velocity, since the net force is zero, we can conclude that the work done by gravity is indeed zero.
C. The work done by gravity equals the work done by air resistance.
This option is incorrect. The work done by air resistance is not equal to the work done by gravity, as the work done by gravity is zero at terminal velocity.
D. The work done by air resistance is 0.
This option is also correct. At terminal velocity, the work done by air resistance is zero, as no net work is being done due to the absence of acceleration.
E. Her kinetic energy increases.
This option is incorrect. At terminal velocity, the skydiver's velocity is constant, meaning her kinetic energy remains constant. There is no increase in kinetic energy.
Therefore, the correct answer is option B: The work done by gravity is zero.
To summarize, at terminal velocity, the work done by gravity and air resistance is zero, and the skydiver's kinetic energy remains constant.