Question

dalvoron can u help @physics

Answer 1

post your question

Answer 2

ishaan can u help??

Answer 3

first post your questions

Answer 4

A gun of mass M fires a shell of mass m horizontally

Answer 5

OKay

Answer 6

and the energy of the explosion

Answer 7

is sufficient to raise the shell to a vertical height h.Show that the velocity of the recoil of the gun is (2m^2gh/(M+m))^1/2

Answer 8

assume that the gun barrel is rigidly attached to a carriage

Answer 9

which is free to move on a frictionless horizontal surface

Answer 10

pls help

Answer 11

well how much potential energy does the shell have at its apogee?

Answer 12

?

Answer 13

do you know the equation for potential energy?

Answer 14

mgh

Answer 15

ishu??

Answer 16

what does "ishu??" mean

Answer 17

pls help

Answer 18

hmm momentum must be conserved

Answer 19

i'm trying

Answer 20

0 = M(V) + m(v - V)

Answer 21

i think the potential energy of the shell at its apogee equals the kinetic energy of the recoil

Answer 22

Sorry it should be
0=MV - m(v-V)

Answer 23

but the question says explosion, is the explosion inside the gun carriage?

Answer 24

dont knw

Answer 25

yes

Answer 26

pls read qn again

Answer 27

hmm then
2gh = MV^2 + m(v - V)^2

Answer 28

V = mv/(m+M)

Answer 29

v = (m+M)/m we should use this

Answer 30

v = (m+M)V/m

Answer 31

energy=mgh, 1/2MV^2 = mgh, right?

Answer 32

hmm, that doesn't come out right, because solving that for v gives sqrt(2)sqrt(g)sqrt(h)sqrt(m)/sqrt(M)

Answer 33

.........

Answer 34

I think it should be mgh = 1/2m(v-V)^2

Answer 35

hey u getting that pals??

Answer 36

what's little v?

Answer 37

i get
\[V=\sqrt{2} \sqrt{{ghm\over M}}\]

Answer 38

i'm not sure if that's the same as when we were asked to prove

Answer 39

ishaan??did u get?

Answer 40

no I didn't
little v is for shell's velocity

Answer 41

when? at the moment of firing?

Answer 42

yeah

Answer 43

we don't know that though, we only know its ultimate height

Answer 44

wait hmmm
2gh = v^2
2gh = (m+M)^2/m^2V^2
2gh(m+M)^2
----------------- = V^2
m^2

Answer 45

what's 2gh?

Answer 46

oh sorry my bad

2ghm^2
-------------- = V^2
(M+m^2)

Answer 47

mgh = 1/2* m v^2

Answer 48

ah i see

Answer 49

u got the answr?

Answer 50

oh wait wait i see where you're going, you clever guy, it's that the initial energy is moving the combined mass of both shell and gun

Answer 51

but I am a little confused I mean for linear momentum conservation I had to use