# 5.6.15 Representing Terminal Velocity

### Representing Terminal Velocity

• A velocity-time graph can show how the velocity of an object changes in time as it reaches terminal velocity
• There are characteristic features of all terminal velocity graphs:
• The gradient (or slope) of a velocity-time graph represents the acceleration of the object
• On any terminal velocity graph, the gradient (acceleration) will decrease from being very large down to zero
• Sometimes the gradient is negative (i.e. showing deceleration, or slowing down)

Debbie the skydiver experiences a large deceleration (her speed decreases suddenly) as soon as she opens her parachute, because of a large resultant force upwards

• The image above shows a skydiver slowing down, due to the large upwards resultant force acting on her
• At this moment in time, the air resistance is larger than the skydiver’s weight (due to the parachute’s huge surface area)
• This results in a large unbalanced force upwards, decelerating the skydiver’s descent
• The graph below summarises how a skydiver’s velocity changes up to and following the point of opening a parachute:

Graph showing how the velocity of a skydiver changes during descent

### Author: Katie

Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.
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