Class Two

Question 1

what is the center of mass

Answer 1

point at which the mass of an object is concentrated

Question 2

when is an object considered moving in a uniform circular motion

Answer 2

when it is moving in a circular path in a constant speed

Question 3

in uniform circular motion, is the velocity constant?

Answer 3

no

Question 4

the acceleration of an object undergoing circular motion always..

Answer 4

points toward the center of the circle

Question 5

what does centripetal mean

Answer 5

seeking the center - describes acceleration in UCM

Question 6

v and a relationship - UCM

Answer 6

velocity is tangent & acceleration points towards the center of the circle → perpendicular

Question 7

magnitude of centripetal acceleration

Answer 7

a_c = v² / r

Question 8

F_net and acceleration always..

Answer 8

point in the same direction

Question 9

what is centripetal force

Answer 9

net force directed toward the center that acts on an object to make it execute UCM

Question 10

F_c = ma_c =

Answer 10

mv² / r

Question 11

what is torque

Answer 11

measure of a force’s effectiveness at making an object spin or rotate - accelerate rotationally

Question 12

what is the pivot point

Answer 12

point that does not move while the remainder of the object is rotation

Question 13

what is the radius vector

Answer 13

vector between the center of rotation and the point of application of the force

Question 14

the amount of torque a force provides depends on.. (3)

Answer 14

magnitude of F

length of r

angle ∅

Question 15

torque formula

Answer 15

Question 16

unit for torque

Answer 16

Newton x meter

Question 17

forces with no torque cannot..

Answer 17

increase or decreases the rotational speed of an object

Question 18

which is negative? counterclockwise or clockwise?

Answer 18

negative: clockwise
positive: coutnerclockwise

Question 19

lever arm method of calculating torque

Answer 19

measure the shortest distance from the pivot to the line along which F is applied

Question 20

lever arm torque formula

Answer 20

torque = ∫ F

Question 21

if a force acts at the pivot or along a line through the pivot..

Answer 21

the torque is zero

Question 22

what does equilibrium mean in physics

Answer 22

zero acceleration (constant velocity)

Question 23

when is a system in static equilibrium

Answer 23

when velocity = 0

Question 24

when is a system in translational equilibrium

Answer 24

if the forces cancel (F_net = 0) → translational acceleration = 0

Question 25

when is a system in rotational equilibrium

Answer 25

if the torques cancel (t_net = 0) → rotational acceleration = 0

Question 26

what measures an object’s inertia

Answer 26

mass → determines its resistance to accelerate

Question 27

the larger the mass, the ___ the inertia

Answer 27

higher

Question 28

what acts as translational inertia

Answer 28

mass

Question 29

what is necessary to produce rotational acceleration

Answer 29

torque

Question 30

what is necessary to produce translational acceleration

Answer 30

force

Question 31

the further away the mass is from the axis of rotation..

Answer 31

the greater the rotational inertia will be

Question 32

what determines rotational inertia

Answer 32

the distribution of an object’s mass relative to the axis of rotation

Question 33

torque is maximized when..

Answer 33

sin90 = 1

(F and r are perpendicular)

Question 34

in static equilibrium, the net torque is _ and the net force is _

Answer 34

zero and zero

Question 35

formula for work

Answer 35

W = Fd

Question 36

work by a constant force formula

Answer 36

W = Fdcos∅

∅ = angle between F and d

Question 37

what is power

Answer 37

measures how fast work gets done

Question 38

power formula

Answer 38

work / time

Question 39

what is kinetic energy

Answer 39

energy due to motion

Question 40

total work down on an object =

Answer 40

change in its kinetic energy

Question 41

what is potential energy

Answer 41

energy an object has by virtue of its position

Question 42

3 types of potential energy

Answer 42

gravitational, electrical & elastic

Question 43

change in gravitational potential energy: + mgh if..

Answer 43

the height of m is increased by h

Question 44

change in gravitational potential energy: - mgh if..

Answer 44

the height of m is decreased by h

Question 45

work done by gravity: path it follows

Answer 45

the work done by gravity depends only on the initial and final heights of the object, not on the path the objet follows

Question 46

what is a conservative force

Answer 46

only depends on the initial and final positions - not the path taken

Question 47

what force is a conservative force

Answer 47

gravity

Question 48

what is total mechanical energy

Answer 48

sum of an object’s kinetic + potential energy

Question 49

conversation of total mechanical energy

Answer 49

if the forces acting on an object are conservative, then the object’s total mechanism energy will remain the same throughout motion

Question 50

examples of simple machines

Answer 50

inclined planes, pulleys, levers etc.

Question 51

mechanical advantage

Answer 51

effort/applied force to be decreased

Question 52

mechanical advantage formula

Answer 52

resistance force / effort force

Question 53

efficiency formula

Answer 53

W output / energy input

Question 54

momentum formula

Answer 54

p = mv

mass x velocity

Question 55

impulse momentum theorem formula

Answer 55

j = delta p (momentum)

Question 56

law of conservation of momentum

Answer 56

delta p sustem = 0

aka total p initial = total p final

Question 57

two types of collisions

Answer 57

elastic and inelastic

Question 58

when is a collision elastic

Answer 58

when the total kinetic energy is conserved (alongside momentum)

Question 59

when is a collision inelastic

Answer 59

when the total kinetic energy is not conserved

Question 60

what is a perfectly inelastic collision

Answer 60

when the objects stick together afterwards

Question 61

angular momentum formula

Answer 61

L = lmv = Iw