Motion

Question 1

What is a scalar, and what scalars have we learned about?

Answer 1

A type of variable that only has magnitude (number value) and no direction. It can only be positive.

Types of scalars: Distance, Height, Speed, and Time

Question 2

What is a vector, and what vectors have we learned about?

Answer 2

A type of variable that only has magnitude and direction. It can positive or negative.

Types of scalars: Displacement, Velocity, and Acceleration

Question 3

What are the positive directions?

Answer 3

Positive x-axis, east, or right
Positive y-axis, north, or up

Question 4

What are the negative directions?

Answer 4

Negative x-axis, west, or left
Negative y-axis, south, or down

Question 5

What is distance?

Answer 5

A scalar quantity that refers tohow much ground an object has coveredduring its motion.

Question 6

What is displacement?

Answer 6

Displacement- a vector quantity thatrefers tohow far your ending point is fromyour starting point

Question 7

What is speed?

Answer 7

Speedis the ratio of distance and time (always positive) Scalar
average speed = distance traveled/ time or s=d/t

Question 8

What is velocity?

Answer 8

Velocityis the ratio of displacement and time (can be + or -) vector
average velocity = displacement/ time, v =∆x/t

Question 9

What is known about someone moving at a constant speed of 10 m/s,

Answer 9

Their speed doesn’t change.
They are not accelerating.
They move 10 meters every second.

Question 10

Position vs time graphs provide what data?

Answer 10

The position of an object at specific times.
The slope of specific time intervals represents the object’s velocity.

Question 11

On position time graphs, what does the slope represent?

Answer 11

Positive slope - is a positive velocity.
Negative slope - is a negative velocity.
A slope of 0 (horizontal line) - the object is not moving.
The steeper the slope the faster the object is moving.
The more horizontal the slope is the slower the object is moving.

Question 12

What is the difference between instantaneous velocity and average velocity?

Answer 12

Instantaneous Velocity- the speed at any giveninstant intime. (Ex: Speedometer)

Average Velocity- the total displacementcovered over the totaltime. It can be used over many instances and is just an average. (Ex: GPS)

Question 13

What is acceleration and what are the three ways an object can accelerate?

Answer 13

The change an object’s velocity (motion).
a = (Vf - Vo)/t

The three ways an object can accelerate is:
-speed up
-slow down
-change direction

Question 14

How are acceleration and velocity related?

Answer 14

If the velocity is changing, the object is accelerating

If the velocity is staying the same (constant), the object is not accelerating.

Question 15

Velocity vs time graphs provide what data?

Answer 15

Positive slope - is a positive acceleration.
Negative slope - is a negative acceleration.
A slope of 0 (horizontal line) - the object is not accelerating and the velocity is constant.
The steeper the slope the larger the acceleration.
The more horizontal the slope the smaller the acceleration.

Question 16

When an object’s velocity and acceleration are going the same direction, what can be inferred?

Answer 16

-The object is speeding up
-The distance between time intervals is increasing.

Question 17

When an object’s velocity and acceleration are going opposite directions, what can be inferred?

Answer 17

-The object is slowing down
-The distance between time intervals is decreasing.

Question 18

When an object is not accelerating, what can be inferred?

Answer 18

-The object is either not moving or moving at a constant velocity.
The distance between time intervals is not changing.

Question 19

What is accelerations definition equation?

Answer 19

a = (Vf -V0)/t

Question 20

What is the kinematic equations that have the following variables?

a, t, Vf, and Vo

Answer 20

Vf =Vo + at

Question 21

What is the kinematic equations that have the following variables?

a, t, Vo, and ∆x

Answer 21

∆x = Vot + 1/2at^2

Question 22

What is the kinematic equations that have the following variables?

t, Vo, Vf, and ∆x

Answer 22

∆x = (Vf - Vo)/2 *t

Question 23

What is parabolic motion?

Answer 23

Parabolic motion is the representation of projectiles move in the air.

Question 24

How is the motion in the x - axis and y - axis related.

Answer 24

They are independent of each other. They do not affect one another.

Question 25

What is the kinematic equations that have the following variables?

a, Vo, Vf, and ∆x

Answer 25

Vf^2 = Vo^2 + 2a∆x

Question 26

What is the kinematic equations that have the following variables?

a, t, Vf, and ∆x

Answer 26

∆x = Vft - 1/2at^2

Question 27

What is free-fall?

Answer 27

An object is in free fall when the only force acting on it is gravity.

ax = 0 m/s^2
ay = -9.8 m/s^2

Question 28

When an object is in free fall and was thrown with an initial vertical velocity, what is its vertical velocity at the highest point?

Answer 28

At the highest point the vertical final velocity Vfy = 0 m/s

Question 29

What is parabolic motion?

Answer 29

Parabolic motion is the representation of projectiles move in the air.

Question 30

When a projectile is shot horizontally with an initial velocity of 10 m/s, what variables should you know?

Answer 30

x I y
ax = 0 m/s^2 I ay = -9.8 m/s^2
Vox = 10 m/s I Voy = 0 m/s

Question 31

Whenever a variable is given at an angle θ, what is the first thing you should do?

Answer 31

Break up into the x- and y- components using the trig functions cos(θ) for x, and sin(θ) for y

Question 32

When an object is shot with a initial velocity Vo at an angle θ, how do you solve for the x- component?

Answer 32

Vox= Vo cos (θ)

Question 33

When an object is shot with a initial velocity Vo at an angle θ, how do you solve for the y- component?

Answer 33

Vox= Vo sin (θ)

Question 34

What is the total velocity or speed, and how do do you solve for it?

Answer 34

The total velocity or speed is a combination of the velocity in the x- and y-axis.

V_total= √(Vx^2 + Vy^2 )

Question 35

When an object is in projectile motion, what can be said about the velocity in the x- and y - axis?

Answer 35

x - axis : the velocity will not change
y - axis : the velocity will change

Question 36

When an object is in projectile motion, what is known about the velocity at the same height in the x- and y - axis and when it is going up and down?

Answer 36

At same heights the velocity in the x - axis will always be the same, while the velocity in the y - axis will be the same magnitude but negative.

Question 37

When an object is in projectile motion and returning to the same height, how is the total time related to the time to highest point?

Answer 37

The total time is twice as big as the time to highest point.

Question 38

When an object is in projectile motion and returning to the same height, what is its vertical displacement?

Answer 38

∆y = 0 m

Question 39

In projectile motion, which axis is used to solve for time?

Answer 39

y - axis

can only solve for time in the x-axis if the horizontal displacement (∆x) is known.

Question 40

When an object travels up, what is the sign of vertical displacement (∆y)?

Answer 40

Positive because displacement is a vector and has direction.

Question 41

When an object travels down, what is the sign of vertical displacement (∆y)?

Answer 41

Negative because displacement is a vector and has direction.

Question 42

An airplane pilot is moving with a velocity v and drops a package. In the absence of air resistance, where is the package relative to the airplane the moment it hits the ground?

Answer 42

Directly below the plane because the are both moving at a constant velocity in the x-axis and not accelerating.