44 terms

Honors Physics Midterm: Norris

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if you hit all bullseyes when throwing darts, you are ____ _____
accurate and precise
if you hit a tight group of darts far from the bullseye, you are _____
precise
list the steps of the scientific method in order
1. state the problem
2. gather information
3. form a hypothesis
4. test the hypothesis
5. analyze data
6. draw conclusions
what's the difference between scientific theory and law? can a theory become a law?
scientific theory: an explanation based on many observations supported by experimental results
scientific law: rules of nature; things that happen in nature are true all the time
a theory can never become a law
give the scientific notation for the following:
milli, centi, kilo
1x10^-3; 1x10^-2; 1x10^3
what is the "origin"?
point at which all variables have a value of zero
what is scalar? examples?
a variable that just has magnitude but no regard for direction; ex: distance, time, temperature, speed
what is displacement? definition and units? can it be negative?
change in position; final-initial; meters; can be negative
what is a vector? examples?
something that has both magnitude and direction; ex: position, velocity, acceleration
what is acceleration? definition and units?
increase in velocity, speeding up or slowing down, a non-uniform motion; m/s^2
using an acceleration vs. time graph, how do you find the velocity?
find the area under the line
using an acceleration vs. time graph, how do you find the acceleration?
find the slope
when you throw a ball in the air, the velocity at the highpoint is? the acceleration at the high point is?
velocity = 0 m/s
acceleration = -9.8 m/s^2
define and understand newtons' 3 laws of motion (give examples of each)
1. an object will stay in motion or an object at rest will stay at rest when there are no acting forces, or when forces are balanced. ex: a rock not moving
2. force = mass x acceleration; if an unequal force is applied to an object, it will accelerate. ex no seatbelt
3. every force is accompanied by an equal bot opposite force. ex: normal force and weight
what is inertia?
the tendency of an object to stay in the same state of motion
when something is moving at a constant velocity, then the acceleration is?
zero
if something on the ground is being pushed eastbound, then the friction force is in the ___ direction
west
when forces on an object are balanced, what does the object do?
the object does not move
what is the difference between weight and mass? what are the units for each? which one is always the same no matter where you go?
weight: changes depending on gravity; Newtons
mass: never changes; kilograms
mass is always the same
give an example of frag force acting on two different types of objects moving at the same speed
drag force of the air is greater on a large truck than on a compact car moving at the same speed
is normal force always pointed straight up or perpendicular to the surface?
perpendicular
when an object is traveling mid-air along a trajectory the horizontal velocity is ___?
constant
a bullet dropped straight down to the ground will take ____ ___ amount of time as a bullet shot straight horizontally at the same time and elevation?
the same
describe the vertical acceleration of an object during projectile motion
it decelerated on the way up and accelerates on the way down
when something is shot off horizontally, the initial vertical velocity is?
0
for an object in uniform circular motion the direction of the velocity is always?
perpendicular to the circle
for an object in uniform circular motion the direction of the centripetal acceleration is always?
pointing towards the center
what is the definition of uniform circular motion?
the movement of an object at a constant speed around a circle with a fixed radius
write kepler's first 2 laws
1. the paths of the planets are ellipses around the sun
2. the planets move faster when closer to the sun
what is the equation for momentum?
p=mv
if two objects are traveling straight towards each other and come to a complete stop when colliding, what can you say about the objects before the collision? (think momentum, mass, velocity)
the momentum is equal but mass or velocity could be different
use the impulse momentum theorem to explain why seatbelts and airbags are important for your face in a car wreck
if you decrease the moment of impact, the force is decreased as well. seatbelts and airbags slow your momentum forward
define elastic and inelastic collisions
elastic: when objects collide without lasting deformation or the generation of heat
inelastic: when colliding objects become coupled or tangled together
give an example of impulse. over what time does an impulse occur?
moment of impact when a golf club hits a golf ball; the amount of time they're in contact
define lever arm?
the distance between the axis of rotation and the applied force
define torque and give an example
the combination of force and lever arm that can cause an object to rotate. ex: wrench loosening a bolt
a regular meterstick versus a weighted meterstick. which hits the table faster when released at the same time with both having the same axis of rotation and radius? what is this due to and what is the equation that can be used to prove this?
the weighted meterstick will hit the table faster than a normal one because the heavier an object, the more resistance to rotation. I=mr^2
which of the following displays no work being done by your hand?
1. picking up a book
2. pushing a book across a table
3. carrying a book across the room
3. carrying a book across the room
does the value of work depend on the time it takes to perform the work?
no
taylor and diana are running up the stairs. they have the same mass. it takes taylor twice as long as it does diana to reach the top. which has more power? which has more work?
diana has more power. they do the same amount of work.
t/f: work depends on the directions of displacement and force
true
if you drop a ball from the ceiling is the ball's potential energy increasing pr decreasing as it's falling? is this potential energy positive or negative as it is falling?
potential energy is decreasing and it is negative
can a football have potential and kinetic energy at the same time?
yes
total energy equals the ___ of kinetic and potential energy
sum