P2.1 (Forces and their effects)

Question 1

What is Hooke’s law?

Answer 1

That the extension of the spring is directly proportional to the load.

Question 2

What two forces affect an object as it falls?

Answer 2

Air resistance

The weight of the object

Question 3

When does an object reach terminal velocity?

Answer 3

When the air resistance is the same as the weight of the object.

Question 4

How does surface area affect the terminal velocity?

Answer 4

A larger surface area and lighter weight will reach terminal velocity quicker

Question 5

When a velocity time graph levels off, what does this mean?

Answer 5

The object has reached terminal velocity

Question 6

What is terminal velocity?

Answer 6

When the object stops accelerating

Question 7

What does the gradient on a distance time graph mean?

Answer 7

The speed

Question 8

The boat accelerates at a constant rate in a straight line. This causes the velocity of the water skier to increase from 4.0 m/s to 16.0 m/s in 8.0 seconds.
Calculate the acceleration of the water skier and give the unit.

Answer 8

Acceleration = difference in velocity / difference in time

16 - 4 / 8 = 12/8 = 1.5

1.5 m/s ^2 ( metres per second squared)

Question 9

How do you calculate resultant force?

Answer 9

Force = mass x acceleration

Question 10

The water skier has a mass of 68 kg.

Calculate the resultant force acting on the water skier while accelerating at 1.5 m/s squared

Answer 10

F = MA
F = 68 x 1.5 = 102 N