Kinematics and Dynamics

Question 1

Vectors

Answer 1

physical quantitates that have both magnitude and direction. this includes displacement, velocity acceleration, and force, among others.

Question 2

Scalars

Answer 2

quantities that are without direction. This may be the magnitude of vectors like speed, or may be dimensionless, like coefficients of friction.

Question 3

How is vector addition accomplished?

Answer 3

Using tip to tail method or by breaking a vector into its components and using the pythagorean theorem.
V = sqr (X^2 +Y^2 )

Question 4

How is vector subtraction accomplished?

Answer 4

Changing the direction of the subtracted vector and then following the procedure for vector addition.

Question 5

What happens when you multiply a vector by scalar changes?

Answer 5

the magnitude may change and may reverse the direction.

Question 6

What is the dot product?

Answer 6

The dot product is the product of the vectors’ magnitudes and the cosine of the angle between them. Multiplying the two vectors using this process results in scalar quantities.
A x B = [A]{B]cos θ

Question 7

what is cross product?

Answer 7

The product of the vectors’ magnitudes and the sine of the angle between them. The right-hand rule is used to determine the resultant vectors’ direction. This produces a vector quantity.
A x B = [A][B] sin θ

Question 8

What is displacement?

Answer 8

the vector representation of a change in position. It is path independent and is equivalent to the straight line distance between the start and end locations.

Question 9

Distance

Answer 9

a scalar quantity that reflects the path traveled.

Question 10

velocity

Answer 10

vector representation of the change in displacement with respect to time.

Question 11

Average velocity

Answer 11

the total displacement divided by the total time.

V= Δx/Δt . V has a line above it

Question 12

average speed

Answer 12

the total distance traveled divided by the total time.

Question 13

instantaneous velocity

Answer 13

is limit of the change in displacement over time as the change in time approaches zero.
V= limit Δt –>0 Δx/Δt

Question 14

instantaneous speed

Answer 14

the magnitude of the instantaneous velocity vector

Question 15

force

Answer 15

any push or pull that has the potential to result in an acceleration

Question 16

gravity

Answer 16

attractive force between two objects as a result of their masses.

Question 17

friction

Answer 17

is a force that opposes motion as a function of electrostatic interactions at the surface between two objects

Question 18

static friction

Answer 18

exists between two objects that are not in motion relative to each other. Can take on many values.

Question 19

kinetic friction

Answer 19

between two objects that are in motion relative to each other. It is a constant value.

Question 20

coefficient of friction

Answer 20

depends on the two materials in contact.

Question 21

Mass

Answer 21

measure of the inertia of an object, the amount of material.

Question 22

Weight

Answer 22

the force experienced by a given mass due to the gravitational attraction to the earth

Question 23

acceleration

Answer 23

the vector representation of the change in velocity over tie. Average or instantaneous acceleration may both be considered, similar to velocity.

Question 24

Newton’s first law, or law of inertia

Answer 24

an object will remain at rest or move with a constant velocity if there is no net force on the object.
Fnet = ma = 0

Question 25

Newton’s second law

Answer 25

any acceleration is the result of the sum of the forces actin on the object and its mass.
Fnet = ma

Question 26

Newton’s third law

Answer 26

any two objects interacting with one another experience equal and opposite forces as a result of their interaction
F AB = – F AB .

Question 27

linear motion

Answer 27

free fall and motion in which the velocity and acceleration vectors are parallel or antiparallel.

Question 28

projectile motion

Answer 28

contains both and x and y component. assuming negligible air resistance, the only force actin on the object is gravity.

Question 29

inclined planes

Answer 29

two dimensional movement. It is often the easiest to consider the dimensions as being parallel and perpendicular to the surface of the plane.

Question 30

circular motion

Answer 30

the best thought of as having radial and tangential dimensions. In uniform circular motion, the only force is the centripetal force, pointing radially inward. Instantaneous velocity vector always points tangentially

Question 31

free body diagrams

Answer 31

representations of forces acting on an object. they are useful for equilibrium and dynamics problems.

Question 32

translational equilibrium

Answer 32

occurs int eh absence of any net forces actin on an object. An object in translational equilibrium has a constant velocity, and may or may not also be in rotational equilibrium

Question 33

Rotational equilibrium

Answer 33

occurs in the absence of any net torques actin on an object. rotational motion may consider any pivot point, but the center of mass is most common. An object in rotational equilibrium has a constant angular velocity; on the MCAT, the angular velocity is usually zero.

Question 34

component vector equation

Answer 34

X = V cos θ Y= V sin θ

Question 35

Determination of direction from component vectors?

Answer 35

θ =tan^-1 Y/X

Question 36

Universal gravitation equation

Answer 36

Fg = Gm1m2/r^2

Question 37

Static friction

Answer 37

0≤ fs ≤ μsN

Question 38

Kinetic Friction

Answer 38

fk = μkN

Question 39

Force of gravity (weight on earth)

Answer 39

Fg = mg

Question 40

Center of mass

Answer 40

x = m1x1 +m2x2 + m3x3/ m1 + m2 + m3 . same for y or z

Question 41

average acceleration

Answer 41

a =Δv/Δt

Question 42

Kinematics, no displacement

Answer 42

V=Vo + at

Question 43

kinematics (no final velocity)

Answer 43

x = Vot + at^2/2 .

Question 44

kinematics no time

Answer 44

V^2 = Vo^2 + 2ax

Question 45

kinematics no acceleration

Answer 45

x = vt . v is average velcoity .

Question 46

components of gravity

Answer 46

Fpara = mg sin θ

F perp = mg cos θ

Question 47

Centripetal force

Answer 47

Fc = mv^2/r

Question 48

torque .

Answer 48

τ = r x F = rF sinθ