Your class notes with problems completely worked out:

**PreAP Projectile Notes-problems worked out**

Also a few notes about your HW:

One reminder: These are all full-trajectory problems. If, in the y-direction, you use the velocity at the top to be zero, recognize that the time you find with this data will be one-half of the total flight time. You can use this time to find the max height, but you will need to double it to find the horizontal (x) distance traveled by the projectile.

Good luck! Email me if you have questions.

#9)

That is a perfect example of a full trajectory problem.

1) You are given the initial velocity to start and it is a vector in both the x- and y-directions. You must break it into x- and y-components, respectively Vx and Voy. Put these numbers into your table of variables just like the example we looked at.

2) If you use the y-direction to solve for time as you must in this problem, you have the positive initial velocity (from #1 above), the negative acceleration of gravity and we know the velocity at the top of its trajectory is zero. If you use this info to solve for time, recognize that you have found the time to go up, and that the total time that you will use in the x-direction is actually twice this much.

#11)

This is a horizontal projectile, but with weird information to start. There is nothing special about it, it just begins with different information than what I used as an example in class.

#16)

This is the hardest problem on the assignment, in my opinion. If you set up your table of x- and y-variables you will have two unknowns in both directions: Vo and t. You can solve this just like a system of equations in math…2 equations, 2 unknowns, one from the x-direction and one from the y-direction. The only tricky part is to do as described in number 1 above…make sure your Vx=Vocos(theta) and Voy=Vosin(theta).

This is sort of your challenge problem on this assignment. I won’t do the rest for you, so give it a good shot.

#17)

This is a tougher problem in some ways than the others since the trajectory is interrupted by hitting the wall. Unlike most of the other problems, you actually start with enough info to find the time it takes to hit the wall by using the x-direction (you know initial velocity, so find Vx and Voy, and use the horizontal distance to the wall). This gets you the time for a and the time you need to use in part b.

**Watch your units! There are non-standard SI units in many questions. Fix them before you begin.**