Terminal velocity

• What is terminal velocity?


  It is the constant velocity reached when an object is no longer accelerating or decelerating.
• What happens to an object when it first steps out of an airplane?


  The object will initially be stationary and then start to fall due to gravity.
• What force pulls an object downwards towards the Earth?

  Gravity
• What is the force that a person feels due to their mass when falling?


  Weight
• How does the weight of a person change as they 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 the resultant force as the person starts falling?


  The resultant force causes them to accelerate downwards.
• What force opposes the weight of a falling person?

  Air resistance
• What is air resistance also known as?


  Drag
• What causes air resistance when a person falls?


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

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


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


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


  The air resistance is low because their velocity is still low.
• What happens to the resultant force as air resistance increases?


  The resultant force decreases as air resistance increases.
• What does it mean when the resultant force is zero?


  It means the object has reached terminal velocity and will no longer accelerate.
• What happens when a person opens their parachute?


  The surface area increases, causing air resistance to increase significantly.
• What is the effect of increased air resistance after opening a parachute?


  The resultant force becomes upwards, causing the person to decelerate.
• What happens to the new terminal velocity when a parachute is deployed?


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


  • Initially, weight is greater than air resistance, causing acceleration.
  • As velocity increases, air resistance increases.
  • Eventually, air resistance equals weight, resulting in no resultant force.
  • The object reaches terminal velocity and continues constant speed.
  • Opening a parachute increases surface area, increasing air resistance and lowering terminal velocity.
• What happens to the resultant force when air resistance equals weight?


  The resultant force becomes zero.
• What is the relationship between acceleration and resultant force?


  When there is no resultant force, there can be no acceleration.
• What is the effect of a sudden change, like opening a parachute, on terminal velocity?


  It causes the object to decelerate and reach a new, lower terminal velocity.