Section 1
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What is distance?
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Last updated
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Date created
Mar 1, 2020
Cards (52)
Section 1
(50 cards)
What is distance?
The length of a path between two points
what causes change in velocity?
A change in direction or a change in speed
What is the SI unit used for acceleration?
A straight line going up on a graph equals what?
a positive constant velocity
what term refers to the product of an objects mass and velocity?
momentum
define constant acceleration
a steady change in velocity
A horizontal line on a distance-time graph indicates what?
that an object is stationary
what is the rate of acceleration due to gravity on earth?
9.8m/s2
does a race car driving around the track at 240 km/h have a constant speed?
yes
what is an object doing if its initial velocity and acceleration are in the same direction?
If the velocity and acceleration are in the same direction (both have the same sign - both positive or both negative) the object is speeding up
in what direction does gravity always cause objects to accelerate?
gravity pulls objects to the ground
a= (10.5 m/s - 0 m/s) / 1.5s
7 m/s2
What does a line that's curving up mean?
speeding up, positive acceleration
while traveling in a car, why do cars that pass by appear to be moving slowly?
Your car is traveling in the same direction as the car passing by
how do initial velocity and final velocity differ?
The initial velocity is the velocity of the object before acceleration causes a change. After accelerating for some amount of time, the new velocity is the final velocity.
define average acceleration
Average acceleration is the final velocity minus the initial velocity per time taken
what is the difference between positive and negative acceleration?
positive is speeding up and negative is slowing down
What is kinematics?
the science of describing the motion of objects using words, diagrams, numbers, graphs, and equations
define velocity
the speed of an object and the direction of its motion
What 4 things are used to graph motion?
displacement Velocity acceleration time
what does the slope of a velocity-time graph indicate?
acceleration
define vector
magnitude and direction
A descending escalator moves at nearly 1 m/s down the incline relative to the ground, and a person walks up the escalator at 2 m/s relative to the escalator. How fast does the person move relative to the ground?
1 m/s
define relative velocity
the velocity of an object in the rest frame of another object
what kind of quantity is acceleration? What information must be include when describing an objects acceleration?
Acceleration is a vector quantity, so you must include both magnitude and direction
A child goes down a slide, starting from rest. If the length of the slide is 2 m and it takes a child 3 seconds to go down the slide, what is the child's acceleration?
a = .44 m/s2
A bird is flying north with a mass of 2.5 kg and has a momentum of 17.5 kg m/s. At what velocity is it flying?
7 m/s
What is displacement?
a vector- has size and direction
A sports car accelerates from rest to 26.8 m/s (roughly 60 mi/h) in 5.1 seconds. what is the acceleration of the car
a = 5.3 m/s2
an in-line skater traveling in a straight line goes from 3 m/s to 9 m/s in 3 seconds. What is the acceleration?
2 m/s2
if a male runner in the fourth starting position ran the 400 m race in 44.40s, how would you calculate his average speed?
V = d/t V = 400m/ 44.40s V = 9 m/s
what are three ways that acceleration can occur?
change in velocity, a change in direction, or a change in both velocity and direction
A straight lone going down on a graph equals what?
back towards the origin in a negative direction
what mathematical operation can you use to determine the relative velocity of an object that is moving perpendicularly to a second object?
find the hypotenuse of the triangle created by the two points that connect through the perpendicular direction
John flies directly east for 20 km, then turns to the north and flies for another 10 km before dodging a flock of geese. Find the distance and displacement.
d = 30 km x = square root of 500 km NE
define frame of reference
a system of objects that are not moving with respect to one another
define scalar
A scalar is a quantity that represents only magnitude. (Time, Temp, Volume)
how can velocity change even if the speed stays the same?
the directions changes
what are the 4 kinematic equations?
Vf = Vi + at d = 1/2 (Vi + Vf)t d = Vi(t) + 1/2 at^2 Vf^2 = Vi^2 + 2ad
what is an object doing if its initial velocity and acceleration are in opposite directions?
If the velocity and acceleration are in opposite directions (they have opposite signs), the object is slowing down.
how far does a sled travel in 5 seconds while accelerating from 4 m/s to 10 m/s?
35m
how do you calculate speed?
By dividing the distance it traveled by the time it took to travel the distance
What is acceleration?
the rate at which velocity changes over time
what does a speedometer measure?
speed of a car (instantaneous speed)
A car with a mass of 1400 kg is traveling at a speed of 40 m/s. What is its momentum?
56,000 kg - m/s
What is the formula for acceleration?
acceleration (m/s2)= final velocity (m/s) - initial velocity (m/s) divided by time (s)
A moving sidewalk at the airport moves about 1 m/s relative to the ground around it. If you work at a speed of 2 m/s relative to the sidewalk, how fast are you moving relative to the ground?
3 m/s
when an object is experiencing "free-fall", what is the only force acting upon it?
gravity
define instantaneous acceleration
Instantaneous acceleration is how fast a velocity is changing at a specific instant.
A fighter jet is catapulted off an aircraft carrier from rest to 75 m/s. If the aircraft carrier deck is 100 m long, what is the acceleration of the jet?
a = 28.125 m/s2
Section 2
(2 cards)