Friction And Force

Question 0

What are two things all forces have?

Answer 0

Size and direction

Question 1

What is a force?

Answer 1

Push or pull

Question 2

What unit is a force measured in?

Answer 2

Newtons (N)

Question 3

What are some examples of a force?

Answer 3

Opening a book with your fingers and sitting in a chair

Question 4

Forces can be _______ and ___________.

Answer 4

Seen and unseen

Question 5

What is net force?

Answer 5

the force that results from combining all the forces exerted on an object.

Question 6

How do you find net force?

Answer 6

Add together the forces moving in the same direction

Question 7

How do you find net force when forces are in different directions?

Answer 7

Subtract the smaller force from the larger force

Question 8

When is the force on an object unbalanced?

Answer 8

When the net force is a number other than zero

Question 9

What causes a change in motion (acceleration) ?

Answer 9

Unbalanced forces

Question 10

What are unbalanced forces necessary for?

Answer 10

To change the motion of moving objects

Question 11

When are e forces on an object balanced?

Answer 11

When the force produces a net force of zero

Question 12

Hat do balanced forces not do?

Answer 12

They do not change the motion of a moving object or cause a nonmoving object to start moving

Question 13

What is friction?

Answer 13

a force that opposes motion between two surfaces that are touching

Question 14

Where does friction occur?

Answer 14

Friction occurs between the surface of an object that is rough. Even surfaces that look or feel smooth are covered with microscopic hills and valleys.

Question 15

The friction between two surfaces includes what?

Answer 15

roughness of the surfaces and the force pushing the surfaces together.

Question 16

The rougher the surface……

Answer 16

The rougher the surface the greater the friction. Smoother surfaces have less friction.

Question 17

The amount if friction depend on what?

Answer 17

The force pushing the surfaces together

Question 18

What happens when the force pushing the surfaces together increases?

Answer 18

the hills and valleys of the surfaces can come into closer contact. This causes friction to increase.

Question 19

_______ objects exert less force than ______ objects do

Answer 19

Less massive/ massive

Question 20

What is sliding friction?

Answer 20

the friction you observe when you are sliding objects.

Question 21

What is rolling friction?

Answer 21

the friction between wheels and the floor when rolling an object.

Question 22

Does rolling or sliding friction exert more friction?

Answer 22

Sliding

Question 23

Rolling friction is an important part of….

Answer 23

All means of transportation

Question 24

What is fluid friction?

Answer 24

friction between an object and water. Fluid friction opposes the motion of objects moving through.

Question 25

What is static friction?

Answer 25

when. A force is applied to an object but does not cause the object to move. The force does not move because the force of static friction balances the force applied. Static friction disappears as soon as an object starts moving and then another type of friction occurs.

Question 26

How can friction cause problems?

Answer 26

Friction causes problems between moving engine parts increasing their temperature and causing parts to wear down. Liquid coolant must be added. It also puts holes in your pants and socks

Question 27

Friction by wind and water causes…

Answer 27

Erosion

Question 28

What are 3 ways to decrease friction?

Answer 28

Applying a lubricant to surfaces can reduce friction.
Using sliding instead of rolling. For example, ball bearings are placed between the wheels and axles of skates and bicycles.
Make rough surfaces smoother.

Question 29

What are 2 ways to increase friction?

Answer 29

Make surfaces rougher. Ex: sand scattered on icy roads keeps cars form skidding.
Increase the force pushing the surfaces together. Ex: putting a heavy rock on a magazine to keep it from blowing away outside.