Physics #1

Question 1

base units

Answer 1

the standard units around which the system itself is designed
Ex: meter

Question 2

derived units

Answer 2

associated base units with each other

Ex: Newton

Question 3

what does the metric system use for length

Answer 3

meters

Question 4

what is the imperial system?

Answer 4

the British system of measurements: foot, pound, second, mile

Question 5

what are the units for energy/work (Joules)

Answer 5

(kg)(m^2)/(s^2)

Question 6

what are the units for Power (watts)

Answer 6

(kg)(m^2)/(s^3)

Question 7

what are the units for force (newtons)

Answer 7

(kg)(m)/(s^2)

Question 8

what are Angstroms, nanometers

Answer 8

angstroms: 1 A = 10^-10 meters
nanometers: 1 nm = 10^-9 meters

Question 9

what are the units for electron-Volts

Answer 9

1.6x10^-19 J

Question 10

what are vectors?

Answer 10

vectors are numbers that have magnitude and direction

Question 11

scalars

Answer 11

numbers that have magnitude only and no direction

Question 12

vector or scalar: displacement

Answer 12

vector

Question 13

vector or scalar: velocity

Answer 13

vector

Question 14

vector or scalar: acceleration

Answer 14

vector

Question 15

vector or scalar: force

Answer 15

vector

Question 16

vector or scalar: distance

Answer 16

scalar

Question 17

vector or scalar: speed

Answer 17

scalar

Question 18

vector or scalar: energy

Answer 18

scalar

Question 19

vector or scalar: pressure

Answer 19

scalar

Question 20

vector or scalar: mass

Answer 20

scalar

Question 21

compare distance and displacement for Earth orbit

Answer 21

the distance Earth travels is 940 million kilometers but its displacement is 0 (circular)

Question 22

what is the resultant of two vectors

Answer 22

the sum or difference of two or more vectors

Question 23

when multiplying a vector by a scalar, what will happen?

Answer 23

it’s magnitude will change but it will remain parallel or antiparallel to the original vector’s direction.

Question 24

how is the idea of work tied into vectors?

Answer 24

Only need magnitude: dot product

work is Force (dot) displacement = |A||B|cos(theta)

Question 25

how is the idea of torque tied into vectors?

Answer 25

Need both magnitude and direction: cross product | |A||B|sin(theta)

Question 26

when do you use cross product vs. dot product?

Answer 26

dot product: just need magnitude of two vectors multiplied cross product: need magnitude and direction of two vectors multiplied RHR: first vector (thumb) x second vector (fingers) = resultant vector (palm)

Question 27

the resultant of a cross product will always be _____ to the plane created by the two vectors

Answer 27

perpendicular

Question 28

For cross product, does AxB = BxA?

Answer 28

no

Question 29

for cross product, if a magnitude is negative, does it matter?

Answer 29

no, just goes into equation as the absolute value.

Question 30

can the magnitude of a vector be negative?

Answer 30

no, it is the length of the vector which has no direction and thus is always positive.

Question 31

displacement

Answer 31

an object in motion experiences a change in position in space

Question 32

the displacement vector connects _____

Answer 32

in a straight line the objects initial and final positions.

Question 33

does displacement or distance take into account the pathway taken?

Answer 33

distance

Question 34

compare velocity and speed

Answer 34

velocity: displacement/time speed: actual distance/time

Question 35

True or false: the instantaneous speed of an object will always be equal to the magnitude of the object's instantaneous velocity

Answer 35

true

Question 36

True or false: the average speed of an object will always be equal to the magnitude of the object's average velocity

Answer 36

false

Question 37

every change in velocity is motivated by a _____

Answer 37

force

Question 38

friction always ______ an object's motion and cause it to slow down

Answer 38

oppose

Question 39

when a car is driving, what type of friction is a tire experiencing?

Answer 39

static friction (the tire is not actually sliding on the road surface but rather it is rolling).

Question 40

kinetic friction will always have a constant value regardless of ____ and _____

Answer 40

the surface area of contact or the velocity of the sliding object

Question 41

is the coefficient of static friction greater than or less than that of kinetic friction?

Answer 41

greater

Question 42

how does the mass of 1kg compare on the moon vs. Earth?

Answer 42

same

Question 43

how does the weight of 1kg compare on the moon vs. Earth?

Answer 43

greater on Earth

Question 44

when an object is thrown, the _____ travels in a simple parabolic pathway

Answer 44

center of mass

Question 45

what is Newton's First law of motion?

Answer 45

F = ma = 0 | an object at rest or in motion with constant velocity will remain that way unless acted upon by a force

Question 46

what is Newton's second law of motion?

Answer 46

F = ma | an object of mass m will accelerate when the vector sum of the forces results in some nonzero resultant force vector.

Question 47

what is Newton's third law of motion?

Answer 47

F(ab) = -F(ba) | To every action, there is always an opposed but equal reaction

Question 48

is Newton's third law dependent on physical contact?

Answer 48

no, force of moon on Earth is same as force of Earth on the moon

Question 49

free fall and kinematics

Answer 49

constant acceleration due to gravity, no air resistance, and does not reach terminal velocity.

Question 50

when drag force is introduced to an object in free fall, what happens?

Answer 50

eventually, the object will speed up enough so that the drag force is equal to the weight of the ball and the ball will then fall with constant velocity according to Newton's first law.

Question 51

True or false: the time it takes an object to reach its max height is the same amount of time it takes to fall to its original height?

Answer 51

true

Question 52

in uniform circular motion, the instantaneous velocity vector is always____ to the circular path

Answer 52

tangent

Question 53

in uniform circular motion, what keeps an object from moving in a tangent to the circular motion and where does it point?

Answer 53

centripetal force | always points radially inward

Question 54

In uniform circular motion, the tangential force is equal to _____

Answer 54

zero

Question 55

at what angle will objects obtain the greatest vertical and horizontal displacement when launched?

Answer 55

vertical: 90 degrees (straight up) horizontal: 45 degrees

Question 56

because force is a vector, the resultant force is simply the ___ of the forces

Answer 56

sum

Question 57

translational equilibrium exists when _____

Answer 57

the vector sum of all the forces acting on an object is 0.

Question 58

the lever arm is _____

Answer 58

the distance between the applied force and the fulcrum

Question 59

torques that generate clockwise rotation are considered ___

Answer 59

negative

Question 60

in translational equilibrium, _____ is 0, while in rotational equilibrium, ____ is 0

Answer 60

net force | net torque

Question 61

the coefficient of friction depends on _____

Answer 61

the two materials in contact

Question 62

do falling objects with different mass have the same acceleration?

Answer 62

yes, gravity acceleration

Question 63

is magnitude positive or negative?

Answer 63

always positive

Question 64

The normal force and frictional force ______ as the angle of the incline increases.

Answer 64

decrease