@IMStuck
Which equation would best help solve the following problem:

Mark launches a toy rocket with an initial vertical velocity of 25 feet per second from a platform that is at ground level. How long will the toy rocket be in the air?

A.

–16t2 – 25t = 0

B.

–4.9t2 – 25t = 0

C.

16t2 + 25t = 0

D.

–16t2+ 25t = 0

ok, for some reason I'm really confused on this one. I think A or B?

Question

@IMStuck 
Which equation would best help solve the following problem:

 

Mark launches a toy rocket with an initial vertical velocity of 25 feet per second from a platform that is at ground level.  How long will the toy rocket be in the air? 
 
 
 

 
 

  

  A. 
 
–16t2 – 25t = 0
   
   

 
 

  

  B. 
 
–4.9t2 – 25t = 0
   
   

 
 

  

  C. 
 
16t2 + 25t = 0
   
   

 
 

  

  D. 
 
–16t2+ 25t = 0
 
ok, for some reason I'm really confused on this one. I think A or B?

aaronq · Answer

It is b, its the same as the kinematic equation "$\sf \Delta y=v_y*\Delta t+\dfrac{1}{2}*(-9.8~m/s^2)*(\Delta t)^2$"

anonymous · Answer

thank you :)

aaronq · Answer

no problem!

aaronq · Answer

Hey i just noticed these units werent SI, so its not B. gravity in these units is 32 $\sf ft/s^2$, so the correct answer is D.

anonymous · Answer

oh alright! thank you for telling me

aaronq · Answer

yeah, no problem. sorry about that