Class Two Flashcards

1
Q

what is the center of mass

A

point at which the mass of an object is concentrated

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2
Q

when is an object considered moving in a uniform circular motion

A

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

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3
Q

in uniform circular motion, is the velocity constant?

A

no

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4
Q

the acceleration of an object undergoing circular motion always..

A

points toward the center of the circle

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5
Q

what does centripetal mean

A

seeking the center - describes acceleration in UCM

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6
Q

v and a relationship - UCM

A

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

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7
Q

magnitude of centripetal acceleration

A

ac = v2 / r

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8
Q

Fnet and acceleration always..

A

point in the same direction

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9
Q

what is centripetal force

A

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

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10
Q

Fc = mac =

A

mv2 / r

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11
Q

what is torque

A

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

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12
Q

what is the pivot point

A

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

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13
Q

what is the radius vector

A

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

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14
Q

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

A

magnitude of F

length of r

angle ∅

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15
Q

torque formula

A
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16
Q

unit for torque

A

Newton x meter

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17
Q

forces with no torque cannot..

A

increase or decreases the rotational speed of an object

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18
Q

which is negative? counterclockwise or clockwise?

A

negative: clockwise
positive: coutnerclockwise

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19
Q

lever arm method of calculating torque

A

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

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20
Q

lever arm torque formula

A

torque = ∫ F

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21
Q

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

A

the torque is zero

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22
Q

what does equilibrium mean in physics

A

zero acceleration (constant velocity)

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23
Q

when is a system in static equilibrium

A

when velocity = 0

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24
Q

when is a system in translational equilibrium

A

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

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25
when is a system in rotational equilibrium
if the torques cancel (tnet = 0) → rotational acceleration = 0
26
what measures an object's inertia
mass → determines its resistance to accelerate
27
the larger the mass, the ___ the inertia
higher
28
what acts as translational inertia
mass
29
what is necessary to produce rotational acceleration
torque
30
what is necessary to produce translational acceleration
force
31
the further away the mass is from the axis of rotation..
the greater the rotational inertia will be
32
what determines rotational inertia
the distribution of an object's mass relative to the axis of rotation
33
torque is maximized when..
sin90 = 1 | (F and r are perpendicular)
34
in static equilibrium, the net torque is _ and the net force is \_
zero and zero
35
formula for work
W = Fd
36
work by a constant force formula
W = Fdcos∅ ∅ = angle between F and d
37
what is power
measures how fast work gets done
38
power formula
work / time
39
what is kinetic energy
energy due to motion
40
total work down on an object =
change in its kinetic energy
41
what is potential energy
energy an object has by virtue of its position
42
3 types of potential energy
gravitational, electrical & elastic
43
change in gravitational potential energy: + mgh if..
the height of m is increased by h
44
change in gravitational potential energy: - mgh if..
the height of m is decreased by h
45
work done by gravity: path it follows
the work done by gravity depends only on the initial and final heights of the object, not on the path the objet follows
46
what is a conservative force
only depends on the initial and final positions - not the path taken
47
what force is a conservative force
gravity
48
what is total mechanical energy
sum of an object's kinetic + potential energy
49
conversation of total mechanical energy
if the forces acting on an object are conservative, then the object's total mechanism energy will remain the same throughout motion
50
examples of simple machines
inclined planes, pulleys, levers etc.
51
mechanical advantage
effort/applied force to be decreased
52
mechanical advantage formula
resistance force / effort force
53
efficiency formula
W output / energy input
54
momentum formula
p = mv mass x velocity
55
impulse momentum theorem formula
j = delta p (momentum)
56
law of conservation of momentum
delta p sustem = 0 aka total p initial = total p final
57
two types of collisions
elastic and inelastic
58
when is a collision elastic
when the total kinetic energy is conserved (alongside momentum)
59
when is a collision inelastic
when the total kinetic energy is not conserved
60
what is a perfectly inelastic collision
when the objects stick together afterwards
61
angular momentum formula
L = lmv = Iw