A-LEVEL Physics: 4.1.14 & 4.1.15: Terminal Speed (Seneca)

Question 1

What is ‘Terminal Speed/Velocity’?

Answer 1

When the Forces of Air Resistance & the Driving Force Reach Equilibrium, the Object Will Reach a Maximum Speed. This Speed is Called Terminal Speed/Velocity.

Question 2

When a Skydiver Jumps out of a Plane, what is his Initial Acceleration?

Answer 2

9.81ms^-2 (Acceleration due to Gravity)

Question 3

As the Skydiver Speeds Up, what happens?

Answer 3

The Number of Air Particles he Collides with per Second Increases.
Hence, the Air Resistance Increases.

Question 4

Throughout the Fall of a Skydiver, his ___ Remains the Same. What does this mean?

Answer 4

Weight.
This means that his Downward Force Remains Constant Throughout.

Question 5

What happens as the Skydiver Speeds Up in the Air? What happens at this Point?

Answer 5

As the Skydiver Speeds Up, the Air Resistance Increases more & more, up Until the Air Resistance Force = Weight of the Skydiver. The Forces Balance Out.
At this Point, the Skydiver Reaches Terminal Speed.

Question 6

The Skydiver will Remain at Constant Speed Unless…

Answer 6

Something Changes, & the Forces of Air Resistance & Weight Acting on him are No Longer in Equilibrium.

Question 7

What happens when the Skydiver Deploys his Parachute? (3)

Answer 7

-The Air Resistance Increases Due to the Extra Surface Area.

-The Resistive Force is now Larger than the Weight of the Skydiver.

-The Skydiver Slows Down- Decelerates.

Question 8

What happens after the Skydiver Deploys his Parachute, & he Decelerates? (3)

Answer 8

-As his Speed Decreases, so does the Resistive Force of Air Resistance.

-The Speed Decreases Until the Resistive Force of Air Resistance is Equal to the Downwards Force of Weight of the Skydiver.

-This gives the Skydiver a new, Smaller, Terminal Speed. It is now Safe for him to Land on the Ground.

Question 9

The Amount of Drag that an Object Experiences is Proportional to its… (2)

Answer 9

-Speed.

-Surface Area.

Question 10

What 3 Factors Determine the Amount of Drag an Object Experiences? (3)

Answer 10

-Speed.

-Surface Area.

-Shape (how Streamlined).

Question 11

The Faster an Object is Travelling, the ___ the Drag Force.

Answer 11

Larger.

Question 12

The Slower an Object is Travelling, the ___ the Drag Force.

Answer 12

Lower.

Question 13

The Larger the Surface Area of a Moving Object, the ___ the Drag Force.

Answer 13

Larger.

Question 14

The Smaller the Surface Area of a Moving Object, the ___ the Drag Force.

Answer 14

Lower.

Question 15

The Shape of an Object can Affect the ___ Forces it Experiences.

Answer 15

Drag.

Question 16

The More Streamlined a Moving Object is, the ___ the Drag Force Will be.

Answer 16

Lower.

Question 17

The Less Streamlined a Moving Object is, the ___ the Drag Force Will be.

Answer 17

Larger.

Question 18

In Reality, Projectiles Travelling Through the Air Experience…
What does this mean?

Answer 18

Air Resistance.
This means that, in a Real Experiment, we Expect the Projectile to Travel Smaller Distances & Reach Lower Speeds than Predicted.

Question 19

What is the Maximum Speed of a Vehicle?

Answer 19

The Maximum Speed of a Vehicle is the Vehicle’s Terminal Velocity Through the Surrounding Air.

Question 20

When does a Moving Object Reach Terminal Velocity?

Answer 20

When:
Resistive Frcitional/Drag Force = Driving Force
Equilibrium

Question 21

To Increase the Maximum Speed of a Vehicle, we Can: (2)

Answer 21

-Reduce the Drag Forces it Experiences, by Making the Vehicle More Streamlined.

-Increase the Driving Force of the Vehicle, by Making the Engine More Powerful.