Ch 3- Forces

Question 1

Forces

Answer 1

Fn-perpendicular to surface
Ff- always opposes motion of object, parallel to surface, dependant on Fn
Fg- points straight down, always included with Fn except in overhead views

Question 2

Net force

Answer 2

Vector sum of all forces

Zero when at rest

Question 3

Tension

Answer 3

Pulling NOT pushing

Look at component its asking for

Question 4

Newton’s first law

Answer 4

Law of inertia (resisting a change in its state of motion)
Object will continue in uniform velocity in a straight line unless an external force acts upon it
No force, Fnet=zero

Question 5

Newtons second law

Answer 5

Law of motion (accel)
When an external force acts on an object, object will accel in same direction as force
F=ma
Accel is inversely proportional to mass & is directly proportional to force
Fnet doesnt equal zero

Question 6

Newton’s third law

Answer 6

Law of action-reaction (objects interracting) force
For every action there is an equal and opposite reaction
Reaction force DOESNT guarantee same reaction accel

Question 7

Mass vs weight

Answer 7

Mass-how heavy it is (g)

Weight-force (N)

Question 8

Static friction

Answer 8

Exists between two sufaces that are not moving
measurement of the max force it can handle
Object only moves if Fparallel is greater than muStatic (force of friction)
Greater than kinetic friction

Question 9

Kinetic friction

Answer 9

Exists between two surfaces that are moving

Question 10

Gravity’s components

Answer 10

F(perp)- Fgcosx

F(para)- Fgsinx

Question 11

Inclined planes

Answer 11

If object moves, need to recalculate Ff using muK

Question 12

Galileo’s thought experiments

Answer 12

Ex 1 & 2-no friction, with no accel object will move at a constant velocity forever (natural motion)