Unit B, Chapter 3 &4

Question 1

(push or pull). a __ is an action capable of acceleration. vector, measured in newtons (N)

Answer 1

Force

Question 2

tendency of a body to maintain its current state of motion. a property that resists acceleration

Answer 2

Inertia

Question 3

an object will remain at constant velocity (includes zero) ina straight line unless acted upon by an unbalanced force.AKA law of Inertia

Answer 3

Newton’s first law of motion

Question 4

The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. a=F/m

Answer 4

Newton’s second law of motion

Question 4

1. Net force ≠ 0
2. Net force = 0

Answer 4

1.unbalanced force
2. balanced force

Question 5

the vector sum of all forces (total)

Answer 5

Net force

Question 6

(weight) always downwards

Answer 6

force due to gravity (fg)

Question 7

(perpendicular to surface) not always opposite to fg

Answer 7

Normal force (fn)

Question 8

always opposes motion

Answer 8

force of friction (ff)

Question 9

points away from object in direction on rope

Answer 9

force of tension (ft)

Question 10

diagram used to represent forces action on a single object. Uses vector arrows. must include: force type,direction, relative motion

Answer 10

Free body diagram (FBD)

Question 11

Object is stationary. Fx=max=0, Fy=may=0

Answer 11

Statics

Question 12

Object is accelerating. Fx=max, Fy=may

Answer 12

Dynamics

Question 13

Every particle in the universe attracts every other particle. This force acts: along a line between 2 particles anf from centre of one object to center of another. Fg=Gm1m2/r2

Answer 13

Newtons law of universal gravitation

Question 14

sphere of influence. used to explain how forces act at a distance

Answer 14

Field

Question 15

force per unit mass, vector

Answer 15

gravitational field

Question 16

always drawn towards the center of an object

Answer 16

field lines for masses

Question 17

small mass placed in the field of another object & therefore experiences a force

Answer 17

test object

Question 18

any mass (since all masses produce fields). typically a celestial body

Answer 18

Producing object

Question 19

g=Gm/r2. the gavitational force per unit mass at a specific location

Answer 19

gravitational field strength

Question 20

Fg=Gm1m2/r2. force that attracts two objects together.

Answer 20

gravitational force

Question 21

for every action (force) in nature there is an equal and opposite reaction.

Answer 21

Newton’s third law of motion

Question 22

mass measurement based on the ratio of known net force on object to the acceleration of object

Answer 22

Inertial mass

Question 23

force initiated by object A on object B

Answer 23

Action force

Question 24

force exerted by object B on object A

Answer 24

Reaction force

Question 25

relates to roughness of contact surfaces.

Answer 25

coefficient of static friction

Question 26

static friction does not have a fixed magnitude. It varies from 0 to max value, which is reached the instant the object starts to move.

Answer 26

Magnitude of static fritction

Question 27

always present when two objects are sliding together.

Answer 27

kinetic friction

Question 28

gravity acts on objects whether or not they are actually touching.

Answer 28

action-at-a-distance force

Question 29

May be more or less than true weight. Magnitude and direction of acceleration and its direction determines how much extra force is being applied to us.

Answer 29

Apparent weight

Question 30

On earth the value of Fg acting alone on a mass at rest

Answer 30

true weight

Question 31

if standing on a stationary surface, the reaction force to Fg that we feel is called __

Answer 31

Weight