Force and Friction

Question 1

A force that opposes motion between two surfaces that are in contact

Answer 1

friction

Question 2

A push or pull exerted on an object

Answer 2

force

Question 3

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Answer 3

Newton’s First Law

Question 4

Net Force equals mass x acceleration (EF=ma)

Answer 4

Newton’s Second Law

Question 5

For every action there is an equal and opposite reaction

Answer 5

Newton’s Third Law

Question 6

a state in which opposing forces or influences are balanced.

Answer 6

equilibrium

Question 7

Force is ________ not possessed (things don’t have force).

Answer 7

applied

Question 8

Force and acceleration are ________ proportional

Answer 8

directly

Question 9

Mass and acceleration are _________ proportional

Answer 9

inversely

Question 10

Force due to gravity acting on mass (measured in pounds or newtons)

Answer 10

Weight

Question 11

Force or gravity of the weight (newtons)

Answer 11

F (g) or W

Question 12

acceleration due to gravity

Answer 12

a (g) or G

Question 13

w = mg OR f = m a(g)

Answer 13

Finding weight

Question 14

sum of all forces

Answer 14

net force

Question 15

Kinetic (sliding), Static (at rest), Rolling (resistance to an object rolling), Fluid (between molecules of liquid or gas)

Answer 15

types of friction

Question 16

Microscopic roughness, molecular attraction,

Answer 16

Causes of friction

Question 17

The velocity where the force of air resistance up equals the weight down. Caused by the flow of air molecules past the surface (ex. skydiving)

Answer 17

Terminal velocity

Question 18

Friction depends on…

Answer 18

Shape? NO

Mass? YES

surface area (ONLY for rolling and fluid, NOT for static and kinetic)

Velocity (Fluid YES, NO for others once object is in motion)

Texture? YES

Question 19

the ratio of the friction to the normal force acting between two objects (measure of “stickiness” of materials in contact)

Answer 19

coefficient of friction

Question 20

Ff/Fn = μ

Answer 20

coefficient of friction equation

Question 21

If a = 0, then

Answer 21

Ff = Fa
Fn = Fg

Question 22

Static friction is ________ than kinetic friction

Answer 22

greater

Question 23

EF = Ff
ma = μFn
ma = μmg
a = μg
EF = ma
Fn = Fg

Answer 23

Equations for acceleration caused by friction