Sift Mechanical Comprehension

Front 1

What are the two types of values in physics?

Back 1

scalars and vectors

Front 2

Explain scalars

Back 2

In most basic math, simple numerical values are calculated, for instance 1 + 1 = 2, these simple numbers are known as scalar values, meaning they have magnitude but no direction. Mass is an example of a scalar value.

Front 3

Explain a vector:

Back 3

Value with magnitude and direction. A vector can tell you how large a value is and if it acts upward, left, right ,etc.

Front 4

___________ is a scalar value that tells you how fast an object is moving.

Back 4

Speed

Front 5

___________ tells you the direction and speed than an object is traveling.

Back 5

Velocity

Front 6

Describe force

Back 6

A push or pull that can result in an object's motion or change of shape, and has magnitude and direction, making it a Vector.

Front 7

What is force measured in?

Back 7

Newtons (N) in the metric system, Pounds Force (lbf) in standard system.

Front 8

Force can be noticed but no seen; what can it be considered as?

Back 8

interaction between two bodies

Front 9

Newton's Laws of Motion are the foundation of the field of _____________.

Back 9

Mechanics

Front 10

Newton's First Law of Motion (Law of Inertia)

Back 10

An object at rest remains at rest and an object in motion will remain in motion until a force is applied. (Soccer ball stays at rest until kicked, eventually stops because of forces [drag, friction] acted upon it)

Front 11

Newton's Second Law of Motion

Back 11

Acceleration of the object will be proportional to the sum of the forces being applied. Algebraically, Newton's second law is written: F = m * a

F = Force

m = Mass; kilograms (kg) or pound mass (lbm)

a = Acceleration; meters/second squared (m/s2) or feet/second squared (ft/s2)

Front 12

______________ is defined as the rate of change of an object's velocity.

Back 12

Acceleration

Notes: Acceleration does not have to result in speed; it can also cause a change in direction, as is the case in centripetal, or rotational, acceleration.

Front 13

Newton's third Law of Motion

Back 13

For every action there is an equal and opposite reaction.

Front 14

Give a Static example of Newton's Third Law

Back 14

Leaning against a wall you apply a force on the wall and the wall applies a force on you. These two forces are the same magnitude but in opposite directions.

Front 15

Give a Dynamic example of Newton's Third Law

Back 15

Cars crashing. One car collides into a stationary car, both cars feel the same amount of force.

Front 16

Centripetal Force:

Back 16

The force that makes an object travel along a curved path. Centripetal force creates centripetal acceleration toward the center of a curved path.

Front 17

Centrifugal force:

Back 17

The reaction force of centripetal force that pulls an object toward the outside of the curved path. The results of centrifugal force is centrifugal acceleration.

Front 18

Give an example of Centripetal and Centrifugal force.

Back 18

When a ball on a string is swung in a circle, the string exerts a centripetal force on the ball, preventing it from leaving the circular path, and the resulting centrifugal force pulls the ball outward, causing tension in the string keeping it taut.

Front 19

Law of Universal Gravitation

Back 19

States that the Gravitational Force two bodies exert on each other is proportional to their masses and inversely proportional to the square of the distance between them.

Front 20

Explain Fg = m * g; Universal Gravitation Equation

Back 20

m = mass; kg or lbm

g = acceleration due to gravity; 9.81 m/s2 or 32.2 ft/s2

Front 21

_____________ is merely a measure of the force of gravity of an object. (m * g)

Back 21

Weight; N or lbf

Front 22

Explanation of weight as a force:

Back 22

Means that an object, such as a book, resting on a table, exerts a force on the table; the table exerts a force of the same magnitude (weight of the object), back on the object.

Front 23

This force exerted back on the object opposing the object's weight is known as _____________.

Back 23

Normal force.

Notes: "normal" because it is normal, or perpendicular to the table. If holding the book in your hands, you must apply an upward force to keep he book stationary; therefore you are supplying the normal force equal to the book's weight.

Front 24

Center of Gravity or Center of Mass

Back 24

Essentially the average location of the object and is often used in physics to simplify problems, treating the object as a single particle with all of its mass at its center of gravity.

Front 25

Torque:

Back 25

or moment due to force, equals the distance of the force from the fulcrum, or pivot point, multiplied by the tangential force: T = F * r

F = force

r = torque arm or distance from the fulcrum

Measured in Newton-meters (Nm) or foot-pounds-force (lbf-ft)

Front 26

The normal force created by gravity also gives rise to a resistance to sliding known as _________.

Back 26

Friction

Front 27

What are the two types of friction

Back 27

Static and Kinetic

Front 28

Static friction

Back 28

is the force of friction between two objects that are not moving relative to each other. (trying to push a refrigerator across a floor; static friction keeps it in place)

Front 29

The force necessary to start sliding an object is called __________.

Back 29

Striction

Front 30

Kinetic friction

Back 30

Once you over come the striction point of an object, Kinect friction will apply a constant opposition no matter how hard or fast force is applied.