Drag And Terminal Velocity (T1)

Question 1

When an object passes through air or liquid what does it come up against?

Answer 1

Air resistance / drag

Question 2

What are the twi significant forces that objects falling through he air experience?

Answer 2

• the weight force (gravitational pull)

- the opposing force

Question 3

How does the speed of a falling object affect the drag?

Answer 3

Drag force increases with the speed of an object

Question 4

What is terminal velocity?

Answer 4

When the friction acting upwards on an object exactly equals the weight of the object, the resultant force is zero so it no longer accelerates.

This is when

Question 5

What is terminal velocity?

Answer 5

When the friction acting upwards on an object exactly equals the weight of the object, the resultant force is zero so it no longer accelerates.

This is when an object has reached its terminal velocity.

Question 6

Explain in stages what happens when a skydiver jumps from a plane and opens his parachute.

Answer 6

• a skydiver jumps from a plane and eventually hits terminal velocity
• this is approx. 200 kph
• when the parachute is opened at that velocity it will cause a sudden increase in the drag fore which is greater than the weight of the skydiver
• the unbalanced force on the parachutist acts upwards and he decelerates

Question 7

The sizes of drag forces in liquids are much ……. than in gases, therefore objects falling through liquids have a much …… terminal velocity

Answer 7

The sizes of drag forces in liquids are much higher than in gases, therefore objects falling through liquids have a much lower terminal velocity

Question 8

How can you model terminal velocity in a lab?

Answer 8

Use a tall measuring cylinder filled with water and drop small diameter (1-2mm) glass beads into it.

Or…

Use a thicker liquid such as glycerine or oil and use small diameter ball bearings.

Measure the terminal velocity using a light gate and a data logger.