Topic 15 - Forces and Matter

Question 1

When stretching, bending or compressing an object, how many forces must act on it?

Answer 1

2

Question 2

Elastic Distortions

Answer 2

• Shape of object is changed under force, but returns to normal after force is released

Question 3

Inelastic Distortions

Answer 3

• Shape of object is changed under force, and stays that way after force is released

Question 4

Hooke’s Law

Answer 4

Extension of elastic object is directly proportional to force applied up to the limit of proportionality

Question 5

Atmospheric pressure varies with height above the Earth’s surface. How?

Answer 5

As height increases, atmospheric pressure decreases as there is less air pushing down

Question 6

Pressure in a Fluid:

Answer 6

Pressure in atmosphere + Liquid

Question 7

Pressure in a fluid causes:

Answer 7

• a force normal to any surface

Question 8

Pressure:

Answer 8

The force exerted over a specified area

Question 9

As depth and density increases, pressure…

Answer 9

increases

Question 10

How does Depth affect pressure?

Answer 10

More depth mean more liquid from on top is pushing down

Question 11

How does Density affect pressure?

Answer 11

• More density means more mass in same volume, meaning more particle collisions

Question 12

Why are objects in a fluid subject to upthrust?

Answer 12

Upthrust occurs due to differences in pressure between the top and the bottom of an object

Question 13

What is upthrust equal to in a fluid displaces

Answer 13

it’s weight

Question 14

How does upthrust influence whether an object will float or sink?

Answer 14

• If upthrust exerts more force than weight, then the object will float

Question 15

How does weight influence whether an object will float or sink?

Answer 15

• If weight is heavier than the force from upthrust, the object will sink

Question 16

How does density of fluid influence whether an object will float or sink?

Answer 16

• If fluid density is more dense than the object, the object will float