Physics Unit Exam Flashcards
what is sigdig short for?
significant digits
do non-zero numbers count towards sigdigs?
YES!
do leading zeros count towards sigdigs?
NO!!!
do in-between zeros count towards sigdigs?
YES!
do trailing zeros count towards sigdigs?
YES!
how do you put something in scientific notation?
-move the decimal to after the first non-zero digit
-like usual, cut and round
-we need to account for the fact that we moved the decimal! to do this, add 10 to the exponent of how many times we moved the decimal.
ex. 12345678=1.23x10^7
how many meters is in a kilometre?
1000
how many millilitres is in a litre?
1000
what is uniform motion?
moving at a constant rate in the same direction
what is average speed?
a change in distance over a given time interval
v=d/t
what does the slope on a distance-time graph represent?
speed!
what does the steepness of a slope tell us?
how fast the object is moving
what does the area on a speed-time graph represent?
distance
how do we calculate slope?
x2-x1
what is a scalar quantity and what is an example?
have a magnitude only; no direction associated with it.
ex. time, mass, distance, speed, energy, work
what is a vector quantity and what is an example?
have both magnitude and direction
ex. displacement, velocity, force, acceleration, deceleration
what is a position?
the separation between an object and its starting point
what does magnitude mean?
size/amount of/how many
is distance a scalar or a vector quantity?
SCALAR!
is displacement a scalar or a vector quantity?
VECTOR!
what is the navigator method?
ex. 30 degrees north of east
what is the Cartesian method?
ex. 97 degrees north of east
what is average velocity?
a change in position over a certain time
v=d/t
what does the slope on a position-time graph represent?
velocity!
what is acceleration?
the change in velocity during a given time interval
a=Vf-Vi/t
what is acceleration measured in?
m/s^2
what does the area on a velocity-time graph represent?
displacement
what is a force?
a push or pull
mass x acceleration
what is force measured in?
newtons(N)
what is mass?
the amount of matter that makes up an object
measured in kg
what is weight?
the force exerted on an object by gravity
measured in newtons(N)
what does the area under a force-displacement graph represent?
work!
what is Newton’s first law of motion?
in the absence of a net force, an object in motion will maintain its velocity, and an object at rest will stay at rest.
what is the formula for work?
W=fd
what is work?
transfer of energy from one object to another
what is energy?
the ability to do work
true or false: work is always equal to energy
TRUE!
what are the three things that must happen for work to have been done?
1) the object must move some distance
2) a force must be applied
3) the direction of movement must be in the same direction as the applied force
what are the 4 common types of kinetic energy?
electrical, thermal, light, and sound
what are the 4 common types of potential energy?
chemical, elastic, nuclear, and gravitational
what is the speed of gravity?
9.81 m/s^2
what is mechanical energy?
the sum of an object’s energy
(kinetic+potential)
what is the first law of thermodynamics?
energy cannot be created nor destroyed. only converted from one form to another
what is the second law of thermodynamics?
no energy conversion is 100% efficient, some energy is always lost as heat when converting from one form to another.
what is efficiency?
a measurement of how much energy input a machine converts into useful output energy
