Position & Motion
What determines the reference point of an object being described?
You do (it's arbitrary or random)
What is the formula used to calculate the average speed or velocity of an object?
v = x/t
On a distance-time graph, a straight horizontal line tells you an object is moving how?
It's not, it's stopped
F = ma is which of Newton's Laws of motion?
2nd
What is the formula used to calculate acceleration of an object?
a = v / t
Motion is described as the process of an object changing its what?
position
___________________ is the measure of the change in velocity during a period of time.
acceleration
On a free-body diagram, the _____ _________ is the sum of all the forces acting on an object.
net force
Newton's 1st Law states an object at rest will stay at rest and an object in motion will stay in motion unless it is acted on by what?
an unbalanced force
Mr. Terry walks from his classroom down to the lunchroom and then back to his classroom. What would be Mr. Terry's displacement in this example?
0 (He wound up back where he started)
What happens when you change the reference point of an object?
You change the description of the object's position
What is the difference between speed and velocity?
Speed tells you how fast you're going, velocity tells you how fast and in what direction you're going.
To determine motion of an object on a free-body diagram, you ______ forces in the same direction and you _______ forces in opposite directions.
add, subtract
Give two examples of Newton's third law.
Forces occur in pairs, for every action there is an equal and opposite reaction
On a distance-time graph, a straight upwards-sloping line tells us what about how an object is moving?
It is moving at a constant speed
What happens to the reference point of an object if that object starts to move or stops moving?
Nothing
What is the difference between distance and displacement?
Distance is the total measure length an object travels, displacement is the shortest straight-line distance between where an object starts at and where an object ends up at.
On a distance-time graph, a curved line with a steep slope indicates what type of change in movement?
Acceleration
In Newton's 2nd Law of Motion, mass and acceleration are ____________ proportional to each other.
inversely
On a free-body diagram, if the same amount of force is applied to an object in opposite directions, what will happen to this object and why?
It will not accelerate because the forces acting on it are balanced
A complete description of the position of an object requires what three things?
A distance, a direction, and a reference point
Mr. Terry is driving his car at 65 m/s. He then accelerates to 70 m/s in 2.5 seconds. What is his acceleration?
2 m/s2
70 m/s - 65 m/s = 5 m/s
5 m/s / 2.5 seconds = 2 m/s2
On a free-body diagram, if you're given the mass of an object, and you know the total force on the object, how do you calculate the acceleration of the object?
Force / Mass = Acceleration
Why is it that a train can't immediately come to a stop and which of Newton's Laws does this relate to?
It has a lot of mass, so it has a lot of inertia and it takes it a while to stop. This is related to Newton's 1st law.
Explain why moving objects don't just keep moving forever.
The force of friction acts on them and slows them down after so long.