Terminal velocity

• What is the main topic discussed in today's video?

  The reason why falling objects reach a terminal velocity.
• What does terminal velocity mean?

  It is the point where an object's velocity remains constant, with no acceleration or deceleration.
• What happens to a person when they first step out of an airplane?

  They are stationary in the air and will begin to fall due to gravity.
• What force pulls a person downwards towards the Earth?

  Gravity, which is felt as weight.
• How does the weight of a person change during free fall?

  The magnitude of their weight remains the same throughout the fall.
• What is the resultant force when a person first steps out of the plane?

  The resultant force is equal to the weight since it is the only force acting on them.
• What happens to a person as they start falling?

  They will accelerate downwards due to the resultant force being equal to their weight.
• What force acts in opposition to weight during free fall?

  Air resistance, also known as drag.
• What causes air resistance during a fall?

  Collisions between the person and tiny air particles.
• What two main factors affect the size of air resistance?

  The surface area of the person and their velocity.
• How does surface area affect air resistance?

  A larger surface area increases the number of collisions with air particles, resulting in greater air resistance.
• How does velocity affect air resistance?

  Higher velocity results in more collisions with air particles, increasing air resistance.
• What happens to air resistance when a person first starts falling?

  It is low because their velocity is still quite low.
• How does the resultant force change as a person accelerates downwards?

  The resultant force decreases as air resistance increases while weight remains constant.
• What does a velocity-time graph show during free fall?

  The graph becomes less steep as the rate of acceleration decreases due to increasing air resistance.
• What occurs when air resistance equals weight?

  The resultant force becomes zero, and the person stops accelerating, reaching terminal velocity.
• What happens to a person when they open their parachute?

  The surface area increases, causing air resistance to increase and resulting in an upward resultant force.
• What happens to the resultant force as a person slows down after opening their parachute?

  The resultant force upwards decreases until it equals the weight again, leading to a new terminal velocity.
• What is the process of reaching terminal velocity when falling?

  • Initially, weight is greater than air resistance, causing acceleration downwards.
  • As velocity increases, air resistance increases.
  • Eventually, air resistance equals weight, resulting in zero resultant force.
  • The object reaches terminal velocity and continues at that speed until a change occurs.
• What happens to terminal velocity when a parachute is deployed?

  The new terminal velocity is lower than the previous one without the parachute.
• What are the key points to recap about falling objects and terminal velocity?

  • Weight is initially greater than air resistance, causing acceleration.
  • Air resistance increases with velocity until it equals weight.
  • At this point, the resultant force is zero, and terminal velocity is reached.
  • Changes like opening a parachute can alter terminal velocity.