15. Air Resistance & Terminal Velocity

Success Criteria

Your learning has been successful if you can do the following:


Learn these so you can communicate this concept well.

Lesson 14: Hei Mahi (Do Now)

Do Now: on Pg 55 of your SciPAD (find a space!)

Draw the triangle to show the relationship between distance, speed and time. 

Draw the triangle to show the relationship between force, mass and acceleration. 

Draw the triangle to show the relationship between speed, time and acceleration.

Do Now: Objects Falling

1. Describe the motion of object A, B and C falling. 

2. Use the graph to calculate the average speed of objects A, B and C

Lesson 4: Exit Task

Find some space on page 15 of your PESS1.2 SciPAD,
and answer the following questions:

What does each letter in CUTLASS stand for? 

Air Resistance

Air resistance, also known as drag, is the force exerted by air molecules on objects moving through the air. It opposes the motion of the object, affecting its speed and trajectory. Air resistance becomes particularly significant at higher speeds or for objects with large surface areas.

There are several factors affecting air resistance:

What is Terminal Velocity?

TERMINAL VELOCITY is the maximum constant speed that a falling object reaches.

Terminal velocity occurs when the force of AIR RESISTANCE / DRAG acting on a falling object becomes equal in size, but opposite in direction to the WEIGHT FORCE.

Explaining Terminal Velocity in the Context of a Skydiver

Initially, when the sky diver jumps out of the plane, the downward force (weight force) is larger than the upward force (air resistance). So, there is an unbalanced force acting on them, causing them to accelerate downward. 

As the sky diver accelerates, air resistance increases, eventually reaching a point where it becomes equal in size, but opposite the direction to weight force. 

At terminal velocity, the downward force (weight force) and upward force (air resistance) are balanced, resulting in a net force of zero and therefore acceleration of zero according to Newton's 2nd law of motion (F=ma). 

The sky diver continues to fall at a constant velocity (terminal velocity), since upwward and downwward forces are balanced. 

Tasks & Homework

Task 1: PESS1.2 SciPAD

Page 14 - Calculating Speed from a Distance-Time Graph

Page 15 - New Zealand Secondary Schools Rally Team


Access your own copy of this homework task on Microsoft Teams. 

Homework - 9. Converting V-T to D-T Graphs