Solving projectile motion equations

[Femme_physics]

Solving projectile motion equations...

Trying to understand this equation...

http://img541.imageshack.us/img541/2658/carqk.jpg

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When you get to the end of this equation, there's s^2 and delta t..

That seems like two unknowns to me. How do they both cancel out?

 

[ZapperZ]

Er... "s" is not an unknown. It is a unit for "seconds".

Zz.

 

[Femme_physics]

Okay, but why is it in second degree? Why did they need to add ^2 into a unit?

 

[ZapperZ]

Okay, but why is it in second degree? Why did they need to add ^2 into a unit?

Er.. it seems that you appear to not know that units can be squared, or undergo the same operations as a variable.

An acceleration, for example, is $L/T^2$, where L is length, T is time. So since the time dimension is squared, the units is also squared. In SI units, it is $m/s^2$. If you don't like the square symbol, then write it as $m/ss$. There, no more squared.

Zz.

 

[jtbell]

If you don't like the square symbol, then write it as $m/ss$.

Or as (m/s)/s: (meters per second) per second.

 

[Femme_physics]

Ah...a little deeper ponderage after your replies got me to see the logic :) mercy.