Easy physics question

[xcellerate]

i need help:
"A 5.8 g bullet leaves the muzzle of a rifle with a speed of 330 m/s. What force (assumed constant) is exerted on the bullet while it is traveling down the 0.89 m long barrel of the rifle?"

It's online homework, i've tried 4 numbers, and I have 1 more try before I miss the problem. I know the majority of you are smarter than i, so i come to you to save me this point! If you could provide a step by step also, i would love you. The answer is in Newtons btw...

 

[Nat Turner]

Vf^2 = Vi^2 + 2ad
330^2 = 0 + 2a(0.89)

solve for a

multiply by .0058

 

[xcellerate]

wow. I totally read that problem the wrong way.

Thanks a ton btw.

 

[Que-Ever]

wow. I totally read that problem the wrong way.

Thanks a ton btw.

you're welcome.

*runs away*

 

[Ikerous]

Vf^2 = Vi^2 + 2ad
330^2 = 0 + 2a(0.89)

solve for a

multiply by .0058

Damn, beat me to it

(I got the same answer though)

 

[losermeetsworld]

42. Always.

 

[jerkasaur]

i don't know why but physics don't appeal to me.
Biology FTW!

 

[short recoil]

sounds like a .380acp bullet to me, taking into account the long barrel.

 

[xcellerate]

if anyone is bored, they can work on this one:

"The air exerts a forward force of 14 N on the propeller of a 0.10 kg model airplane. If the plane accelerates forward at 2.0 m/s^2, what is the magnitude of the resistive force exerted by the air on the airplane?"

It's the last problem, so by the time i reach it, maybe somebody will have an answer

 

[Nat Turner]

if anyone is bored, they can work on this one:

"The air exerts a forward force of 14 N on the propeller of a 0.10 kg model airplane. If the plane accelerates forward at 2.0 m/s^2, what is the magnitude of the resistive force exerted by the air on the airplane?"

It's the last problem, so by the time i reach it, maybe somebody will have an answer

F=MA
14=0.10(A)
A=140

140 - 2 = 138

F=0.10 * 138
F=13.8 N

Is probably correct.. but the wording of the problem is kinda messed up.

 

[Ennui]

Oh god. That reminds me of the huge physics worksheet I have to do tonight.

 

[15357]

While? I thought there would be nothing except air resistance and/or inertia.

I probably read the problem wrong or I need to work on my physics more.

 

[Neutrino]

F=MA
14=0.10(A)
A=140

140 - 2 = 138

F=0.10 * 138
F=13.8 N

Is probably correct.. but the wording of the problem is kinda messed up.

Ya, 13.8N is right, though a more clear way to do it is just draw a free body diagram so you get F1 - F2 = ma, so 14N - F1 = (0.1kg)(2m/s^2) and F1 = (0.1kg)(2m/s^2) - 14N = 13.8N.

 

[Dan]

Someone do my homework for me too:

A water timer constructed from Plexiglas is timed for 12 minutes and it is found that the water level inside has dropped by 6 cm. Assuming the water level decreases at a constant rate, determine the diameter D1 at the top of the water timer where its depth w is 40 cm. Exit diameter D0 at the bottom of the timer is 0.6 cm and the correlation constant C for Torricelli's Law is 1.

 

[Glirk Dient]

Someone do my homework too. If a person whos name is..say klrig is traveling at -93595335 miles on the damn freeway because of POS traffic and shitty weather. The destination he is trying to reach usually takes 30 mins to get to and another 30 back. If he leaves at 3:40 and plans to spend 15 or so mins at his destination shooting badass airsoft guns and possibly buying one then what is his expected arrival time back? It doesnt ****ing matter because traffic is a POS ****er and he was an hour late to work when he was supposed to be there by 6:15.

How many bullets will klirg need to buy to shoot people so he can satisfy his anger for traffic and shitty weather?

 

[Razor]

sounds like a .380acp bullet to me, taking into account the long barrel.

330m/s is relatively slow though, i would of thought only a pistol would fire that slow nowadays.

 

[Dan]

.22s are usually subsonic. Barrel could be 89 cm too. Although I'm not a gun person so I woldn't really know. 22 caliber is what we use for ballistic labs because they don't make as much noise and probably wouldn't kill anyone if somehow something went wrong.