Kinematics & Dynamics

Question 1

SI Units

Answer 1

Length = meter, Mass = kilogram, Time = second, Current = ampere (coulomb/second), Amount of a substance = moles, Temp = kelvin, Luminous Intensity = candela

Question 2

Base unit

Answer 2

The standard units around which the system (SI) is designed

Question 3

Derived unit

Answer 3

Associating base units with each other

Question 4

Newton

Answer 4

Unit of force.

1 kg x m/s^2

Question 5

Derived force unit

Answer 5

Newton

Question 6

Derived work/energy unit

Answer 6

Joule

kg x m^2/s^2

Question 7

Derived power unit

Answer 7

Watt

kg x m^2/s^3

Question 8

Vectors

Answer 8

Numbers that have magnitude and direction

Displacement, velocity, acceleration, force

Question 9

Scalars

Answer 9

Numbers that have magnitudes only and no direction

Distance, speed, energy, pressure, mass

Question 10

Resultant

Answer 10

Sum or difference of two or more vectors

Question 11

Pythagorean Theorem

Answer 11

X^2 + Y^2 = V^2

Question 12

Component method

Answer 12

Used to find the Resultant. Add all X and Y sides together then use Pythagorean theorem to find resultant

Question 13

Vector Subtraction

Answer 13

Can be accomplished by adding a vector with equal magnitude, but opposite direction, to the first vector.
A - B = A + (-B)

Question 14

Dot product

Answer 14

Used to generate a scalar quantity from two vectors. The absolute values of A . B cos angle

Question 15

Cross product

Answer 15

Used to generate a third vector like Torque.
The absolute values of A x B sin angle. The resultant of cross product is always perpendicular to the plane created by the two vectors

Question 16

Displacement

Answer 16

Vector quantity that has both magnitude and direction, but does not account for the actual pathway taken between initial and final positions (a full circle would mean 0 displacement) x or d
v = change in x/change in time
v is average velocity, change in x is change in position

Question 17

Distance

Answer 17

Scalar quantity that takes into account the pathway taken (italic d)

Question 18

Velocity

Answer 18

A vector measured as the rate of change of displacement in a given unit of time, units are meters/second

Question 19

Speed

Answer 19

Measured as the rate of actual distance traveled in a given unit of time

Question 20

Instantaneous speed

Answer 20

Always equal to the magnitude of the object’s instantaneous velocity (v), which is the average velocity as the change in time approaches zero

Question 21

Average speed

Answer 21

Measure of distance traveled in a given period of time

Question 22

Average velocity

Answer 22

Measure of displacement of an object over a given period of time

Question 23

Gravity

Answer 23

Attractive force felt by all forms of matter. acceleration due to gravity, g, decreases with height above the earth and increases the closer one gets to the Earth’s center of mass.. g = 10 m/s^2

Question 24

Gravitational force

Answer 24

Fg = Gm1m2/r^2
Magnitude of gravitational force between two objects
r = distance between their centers of mass
G is universal gravitational constant (6.67 x 10^-11 N x m^2/kg^2)
*If r is halved, Fg will quadruple b/c force is inversely related to the square of distance.
*If m1 is tripled, then Fg will triple b/c mass is directly related to force

Question 25

Friction

Answer 25

Type of force that opposes the movement of objects.

Two kinds: Static & Kinetic

Question 26

Static friction

Answer 26

Exists between a stationary object and the surface upon which it rests.
f_s=µ_s N
µ_s is the coefficient of static friction
N = normal force

Question 27

Normal force

Answer 27

component of the force between two objects in contact that is perpendicular to the plane of contact between the object and the surface upon which it rests.

Question 28

Kinetic friction

Answer 28

Exists between a sliding object and the surface over which the object slides.
f_k=µ_k N
* the coefficient of static friction will always be larger than the coefficient of kinetic friction b/c it always requires more force to get an object to start sliding than it takes to keep an object sliding

Question 29

Mass

Answer 29

Measure of a body’s inertia–the amount of matter in an object (kg is SI unit)

Question 30

Weight

Answer 30

Measure of gravitational force. Fg w/ unit of Newton

Fg = mg where m is mass and g is acceleration due to gravity (9.8 m/s^2)

Question 31

Translational equilibrium

Answer 31

Exists only when the vector sum of all of the forces acting on an object is zero

Question 32

First condition of equilibrium

Answer 32

When the vector sum of all the forces acting on an object is zero

Question 33

Zero acceleration means

Answer 33

Zero net force! This means tat any object with a constant velocity has no net force acting on it. However, just because the net force equals zero does not mean the velocity equals zero.

Question 34

Rotational motion

Answer 34

Occurs when forces are applied against an object in such a way as to cause the object to rotate around a fixed pivot point (fulcrum). Torque (moment of force) happens at some distance from the fulcrum and is termed the lever arm

Question 35

Rotational equilibrium

Answer 35

Exists only when the vector sum of all the torques acting on an object is zero.

Question 36

Second condition of equilibrium

Answer 36

The vector sum of all torques acting on an object is zero

Question 37

Clockwise rotation

Answer 37

Considered negative Torque

Question 38

Counterclockwise rotation

Answer 38

Considered positive Torque