Module 1 Chp 2 Forces and Shape

Define "drag."

Objects experience friction when they move through a liquid or a gas.

What does weight equal ??

Weight only equal to gravitational force

Define "upthrust."

The upward force from a liquid/gas that makes some things float.

Define “weight.”

The gravitational force on an object

Define “tension.” 

The force in a stretched material

OBJQ

Define "friction."

The force that opposes that motion of one material sliding past another

Define “thrust.”

The forward force from an engine

Define “air resistance.”

What is a balanced force?

When resultant force = 0, so a = 0

What are 2 scenarios that a = 0?

If an object is originally at rest, it will continue at rest 

If object move with certain velocity, will move with same constant velocity, so a = 0rest.

What is Newton’s first law?

-There is no net external force acting on an object; if an object is initially at rest, it will continue to rest. If an object moves with a certain velocity, it will continue moving with the same constant velocity. So there is not acceleration.

Explain the relationship between thrust and drag.

Thrust>Drag (Speeding up)

Thrust<Drag (Slow down)

What is Newton Second Law

he resultant force acting on an object is equal to the product of mass and acceleration of the object

F = ma

F = resultant force

m = mass 

a = acceleration

Downward arrow reaction or action?

action

Upward arrow reaction or action?

Normal reaction

When does an action-reaction pair occur?

It occurs when 2 objects interact with each other. (not only on single object)

What is Newton’s Third Law?

Whenever 2 objects interact to each other, the force exerted by the first on the second is equal in magnitude and opposite in direction to the force exerted by the second on the first. This is an action-reaction pair.

When does free fall occur?

When there is no air resistance

What are the other names for free fall? And its symbol

Acceleration due to gravity 

Acceleration of free fall

Symbol = g

What is the upward and downward reaction with gravity and speed?

Upward→against gravity→speed decrease

Downward→same direction with gravity→speed increase

What are free fall equations?

What are the relationships between the same mass and different force and the same force and different masses?

Same mass

F1 > F2

a1 > a2

accelration (a) directly proportional to F (force)

Same force

m1 < m2

a1 > a2

acceleration (a) inversly proportional to mass.