Projectile Motion Question

[deleted92121]

Rocket fired straight up at velocity of 1420 m/s. It releases parcel at 19200 meters. Find how long it takes to hit the ground.

I am not sure if I did it right. Do you actually have to use an equation with g in it. I did it without and think I messed it up that way. Using g would've made it real world where my way was in a world devoid of gravity.

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[dmf2682]

Rocket fired straight up at velocity of 1420 m/s. It releases parcel at 19200 meters. Find how long it takes to hit the ground.

I am not sure if I did it right. Do you actually have to use an equation with g in it. I did it without and think I messed it up that way. Using g would've made it real world where my way was in a world devoid of gravity.

Yeah, gravity is kind of necessary. You also need to say if the rocket is still going up when it released the parcel.

 

[deleted92121]

Yeah, gravity is kind of necessary. You also need to say if the rocket is still going up when it released the parcel.

Rocket stops at the top. So Vfy going up is equal to Voy on way down. What I didnt take into account was gravity. At least I'll get 3/4 credit or so on that one.

 

[discowisco]

So how do you solve this? Is this an MCAT question or from another book? I would have 19200 meters/ 9.8 to get the time, would that work?

 

[deleted92121]

So how do you solve this? Is this an MCAT question or from another book? I would have 19200 meters/ 9.8 to get the time, would that work?

It's from another book. And no not quite.

 

[dmf2682]

I dunno man. If you ignored gravity you kind of missed the point. I might give you 10% for trying but that's pushing it.

 

[Wagz]

Your looking for the time it takes for the parcel to free fall so gravity is essential for credit. Since its freefall its 1 dimensional in the y axis so a good starting point would be....Dy=Vi*T-1/2G*T^2 in my opinion which gives a time of ruffly 62.6 seconds of freefall

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[deleted92121]

Your looking for the time it takes for the parcel to free fall so gravity is essential for credit. Since its freefall its 1 dimensional in the y axis so a good starting point would be....Dy=Vi*T-1/2G*T^2 in my opinion which gives a time of ruffly 62.6 seconds of freefall

Sent from my MB886 using SDN Mobile

My prof gives credit for everything.

And I freaking have 63 written on my sheet when I figured it out with g I just remembered. That may help.