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# Projectile motion with ordered set notation

Solving the second part to the projectile motion problem (with wind gust) using ordered set vector notation. Created by Sal Khan.

## Want to join the conversation?

• why the acceleration is -32m/s2 rather than -9.8m/s?
• He is using feet as the unit of length and 32 ft/s^2 is the acceleration due to gravity using feet instead of meters.
• How can he take the velocity of ball in feet per sec and velocity of wind in m/s??
Isn't this wrong??
• YES, it is wrong, you cannot calculate with different units in each case. Either it was a slip of tongue (or brain as referenced above) or a failure to read the initial question.
• Could someone reference the video in which he's referencing about modifying.
I would so appreciate it.
• Where is this original problem that is referred to here? I didn't come across it. Can someone link me to it?
• Surely we do not need 4k for educational videos but that is hard on the eyes. Would you publish a "draw-over" if I create one?
• At , why must 109t = 350?? Where does 350 come from?
• What are position vectors? And what are displacement vectors? In what video can I find them?
• If you're looking at vectors, then "position" and "displacement" are the same. They just indicate in what direction and how far an object is compared to a reference point.