Physics Unit 2 Test

What was one of Aristotle’s many wrong conclusions?

that heavy objects fall faster than light objects

What was the conclusion about heavy and light objects falling time?

objects accelerate at the same rate despite their mass

What causes certain objects to fall faster or slower?

air resistance

Aristotle

Ancient Greece, approached science, especially classification, logically. However, he got some physics concepts wrong 

What did ibn Al-Haytham argue for?

empiricism (observation and experimentation)

What did ibn Al-Haytham do?

he worked in optics. He designed experiments to prove that the eyes don’t shoot out rays to see things

What did Galileo Galilei establish?

that heavier objects don’t free fall faster by dropping two items from the Leaning Tower of Pisa

What did Galileo theorize?

that air resistance slowed feathers from falling faster rather than lack of mass

What is the order of the 3 philosophers we talked about? 

Artistotle, ibn Al-Haytham, Galileo Galilea

What does constant acceleration look like on a spark tape?

dots start off close together then move to be very spread out 

What is acceleration?

change in velocity 

What is velocity?

speed with direction

What is air resistance?

a subset of friction

What are the 3 equations at the top of the formula sheet?

kinematics equations 

What is kinematics?

the study of motion/moving objects

What is the variable v?

velocity

What is the variable x?

distance

What is the variable a?

acceleration

What is the variable t?

time

What should you do when you graph data and create a line of best fit?

ignore the actual data and only use the line of best fit

What does a time vs velocity graph generally look like?

linear

What does a time vs position/distance graph generally look like?

quadratic 

What are the 5 ways to model motion?

Numerically (table), oil drop, equations, motion graphs (position vs time and velocity vs time)

What is direction indicated by?

positive and negative

If you’re not given in a problem which way is positive or negative then…

it is your choice 

What does it mean when signs of velocity and acceleration are opposite?

the object is slowing down 

What does it mean when signs of velocity and acceleration are the same?

the object is speeding up 

What are vectors?

measurements that have both  magnitude and direction (ex. velocity, displacement, force)

What are scalars? 

measurements having only magnitude (ex. mass, temperature, distance, speed)

What does the slope of a position vs time graph give you?

speed/velocity

How do you find the velocity from a position vs time graph?

calculate the slope as you normally would

What does the slope of a velocity vs time graph give you?

acceleration

What does the area under a velocity vs time graph give you?

distance/displacement

What are the steps to solving an equation?

Draw it, list knowns/unknowns, pick an equation, rearrange the equation if necessary, plug in and solve, reality check 

What are the two kinds of tensors?

vectors and scalars

What is magnitude?

a numerical value

What are vectors represented with?

an arrow

If not given a specific frame of reference, what should you use?

the surface of the Earth

When do you use a frame of reference?

when dealing with anything relative

What is a frame of reference?

a perspective or viewpoint for observing motion, that captures movement from a particular point.

If not given a specific coordinate system, what do you do?

you define it. Assume it’s a visual x-y plane

What does negative velocity mean?

the object (its velocity) is moving in the negative direction

What does negative acceleration mean?

the object is accelerating in the negative direction

What is the variable g?

gravity on Earth

What does acceleration tell us?

if velocity change is constant or just how it is changing 

When does instantaneous speed equal the average speed?

at the midpoint

What conclusion can be made from comparing the slopes of a position vs time² graph and a velocity vs time graph?

the slope of the position vs time² graph is half the slope of the velocity vs time graph. We can conclude that they are the same slopes based on the scale of the numbers

What is the acceleration value due to gravity?

10 m/s²

True or false: with no air resistance, a feather and a rock will fall with the same acceleration

True

True or false: an object can have a negative position

true

True or false: an object can have a negative velocity

true

True or false: an object can have a negative acceleration

true

Is it possible to have positive velocity and negative acceleration?

Yes, it means it’s slowing down 

Is it possible to have zero velocity and negative acceleration?

Yes. For example, when throwing a ball, always accelerating at the same rate but before it goes back down at the top, it stops (0 velocity)

What does displacement depend on?

direction

True or false: a negative acceleration means that an object must be slowing down 

false

If an object has zero velocity and zero acceleration then it must be…

stationary (not moving)

If an object has positive velocity and zero acceleration then it must be…

moving with a constant speed

If an object has positive velocity and positive acceleration then it must be…

speeding up

If an object has negative velocity and positive acceleration then it must be…

slowing down

The idea of acceleration may be characterized in the equivalent words of…

rate of change of velocity

A basketball player jumps to make a shot. Once her feet are off the ground, the jumper’s acceleration…

is exactly g

A ball is thrown straight up. At the top of its path, it’s speed is…

0 m/s²

A ball is thrown straight up. At the top of its path, it’s acceleration is…

about -10 m/s²