CIE A Level Physics复习笔记3.1.7 Terminal Velocity
Terminal Velocity
- For a body in free fall, the only force acting is its weight and its acceleration g is only due to gravity.
- The drag force increases as the body accelerates
- This increase in velocity means the drag force also increases
- Due to Newton’s Second Law, this means the resultant force and therefore acceleration decreases (recall F = ma)
- When the drag force is equal to the gravitational pull on the body, the body will no longer accelerate and will fall at a constant velocity
- This the maximum velocity that the object can have and is called the terminal velocity
A skydiver in freefall reaching terminal velocity
- The graph shows how the velocity of the skydiver varies with time
- Since the acceleration is equal to the gradient of a velocity-time graph, the acceleration decreases and eventually becomes zero when terminal velocity is reached
Worked Example
Skydivers jump out of a plane at intervals of a few seconds.
Skydivers A and B want to join up as they fall.
If A is heavier than B, who should jump first?
- Skydiver B should jump first since he will take longer to reach terminal velocity
- This is because skydiver A has a higher mass, and hence, weight
- More weight means higher acceleration and hence higher speed, therefore, A will reach terminal velocity faster than B
Exam Tip
- Exam questions about terminal velocity tend to involve the motion of skydivers as they fall
- A common misconception is that skydivers move upwards when their parachutes are deployed - however, this is not the case, they are in fact decelerating to a lower terminal velocity
- What do you think this would look like on the graph above?
转载自savemyexams
以上就是关于【CIE A Level Physics复习笔记3.1.7 Terminal Velocity】的解答，如需了解学校/赛事/课程动态，可至翰林教育官网获取更多信息。
往期文章阅读推荐：
重磅！CAIE明年提前出分，爱德思理科也迎大改！这届考生如何破局？
EDX考前急救！只讲高频考点！2027年1月A-Level大考，如何用12小时极限冲刺A*？
翰林AMC8视频课重磅上线！
