Drag And Terminal Velocity

Question 1

What are the two main types

Answer 1

1) contact friction (solids) normally just friction

2) fluid friction (liquid/gas-flow) drag, fluid resistance, air resistance

Question 2

What does fluid friction depend on

Answer 2

Thickness (viscosity) of fluid
Speed
Size of object

Question 3

What 3 things do t need to remember about frictional forces

Answer 3

1) act in opposite direction or motion of object
2) never can speed things up or start things moving
3) convert kinetic energy into heat

Question 4

Terminal velocity is when what

Answer 4

The driving force equals the friction force

Question 5

What two things do you need in order for something to reach terminal velocity

Answer 5

1) driving force which remains constant

2) frictional or drag force that increases with speed

Question 6

What are the 3 main stages of reaching terminal velocity

Answer 6

1) ACCELERATION from rest using a constant DRIVING force
2) as velocity increases resistance forces INCREASES.
This reduces the RESULTANT force which reduces the ACCELERATION
3) eventually it reaches a velocity where the resistance forces are equal to the driving force. There is no RESULTANT force, and no ACCELERATION so is traveling at a CONSTANT. Velocity.

Question 7

Friction does what

Answer 7

Opposes motion

Question 8

Sketching a graph for terminal velocity
Velocity time graph
Acceleration time graph

Answer 8

VT- opposite diode

AT- negative steep, shallow

Question 9

After reaching terminal velocity what happens when the sky diving pulls the parachute

Answer 9

1) immediately INCREASES air resistance now BIGGER than weight
2) SLOWS him down speed dropped enough to equal his weight again
3) new terminal velocity is small enough to survive landing

Question 10

What is the velocity time graph for a sky diving pulling a parachute

Answer 10

Vt at