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Flashcards in Forces and Motions Deck (14):

What is speed?

The amount of time taken for an object to cover a distance.


What is velocity?

The speed of an object in a certain direction.


What is acceleration?

The rate of change of velocity.


What is Newton's First Law?

An object will either remain stationary or move in a straight line at a constant speed, unless there is a resultant force acting upon it.


What is Newton's Second Law?

force = mass * acceleration


What's Newton's Third Law?

Every action has its equal opposite reaction.


What is weight?

The force acting on an object due to the pull of gravity.


What is terminal velocity?

An object falls at a constant velocity in a fluid, because the forces acting on it are equal.


What are the stages of terminal velocity, in a person falling from the sky?

1. Weight is greater than air resistance, so the person will accelerate.
2. Weight is still greater than air resistance, so she will still accelerate, but air resistance is increasing.
3. The forces of weight and air resistance are equal so she no longer accelerates (terminal velocity).
4. Air resistance is now greater that weight, so she will decelerate.


What is density?

It's mass per unit volume.


The effect of distance on the moment and force.

The further the lever is from the pivot, the less the force that will be needed.


What is the Principal of Moments?

moment clockwise = moment anti clockwise

Fcw = Facw


What is a fluid?

Matter where the particles are free to flow past each other.
Particles collide and exert a pressure on the surroundings.


What is pressure?

A force acting upon an area.