When dealing with two dimensional motion, you can decompose all vectors into horizontal and vertical and deal with each one separately.
Let's review the equations we have seen so far.
this equation tells you that velocity v is
in 1D, a question using this equation might look like this - Hannah starts her sprint at 10m left of the door and ends her spring after 5 seconds 15m right of the door. Use the equation above to find Hannah's velocity. We are going to call the direction to the right positive.
I'm stepping you through that one just to make sure - The initial position is -10 (because it is to the left of the door, it is negative). and the final position is 15, which is positive because it is to the right of the door. If I want to find the distance between them, I would subtract .
what does finding the displacemeent look like in 2D? Saw you start at
put the initial point and final point on the graph below (it doesn't let you add a line or an arrow, convince yourself which direction it should go. )
in 2d, you do the EXACT same thing as 1D. you subtract the final point from the initial point. If you start at
do you have any questions about this?
If you have a plane that has a velocity of
The final velocity for the above problem is
If you have a plane that in a windless day has a velocity of
Watch the following video
do you have any questions?think about the kid who throws a ball straight up in the air in a car. Explain why his answer, the ball would land right back down on the person, would only work in ideal physics land.
if you throw a ball straight up in the air when you are driving in a non-convertible car, does the ball whack you in the face because of projectile motion?
when the velocity in the y direction is 0
initial x and y direction, and where the initial velocities in the x and y directions would be measured.
a point where my y velocity is negative
when the y position is 0
a point where my y velocity is positive
Consider the following question - a cannon is shot with an initial velocity of
Using the GUESS method:
Givens - = 3 m/s, =5 m/s, = 0m, =1 m, =4 s, = -10
Unknowns
Which equation do i want? (you may want to look at the equation material on google classroom.
Equations I want in verbal form
equation I want in symbol form
SUBSTITUTE: Which of the following represents the correct values being substituted into the correct equation?
SOLVE: how far did the cannonball move horizontally?
Consider the following question - a cannon is shot with an initial velocity of 2
Using the GUESS method:
Givens - = 2 m/s, =6 m/s, = 0, =1 m, = -10 m/s
Unknowns
Which equation do i want? (you may want to look at the equation material on google classroom.
Equations I want in verbal form
equation I want in symbol form
Substitute: which equation works for what you are trying to find?
consider the following problem: the hangtime of a basketball player who jumps a vertical distance of 2 feet (0.6 m) is about 2/3 s. what will be the hangtime of a player that can jump 1.4 feet (1.2 m) horizontally?
what equation would be best for working this out?
What is your intuition of what the answer is?
Can you prove it using the equation? how?
A cannonball is fired and you are given the following information
Initial velocity =
total horizontal distance when it hits the ground = 7 m
acceleration due to gravity = 10 m/s^2
acceleration in the x direction = 0
you are asked how far off the ground the cannonball is fired from.
you would have to use both position AND velocity equations to solve this. Without doing any math, explain what your unknowns are, which equation you would use to find one, and then which equation you might use to find the other.
How are you feeling about each of these
how to determine what your givens are
how to determine what your unknown is
how to figure out which equation to use
how to use the equations
whether or add or subtract vectors
Using two equations to solve one problem
I've got this
I'm fuzzy
so confused