2
Problem 1 (70 points) The most powerful cannon o ever see action was "Schwer Gustav" (Heavy Gustav) which was used by ' Germany n the siege of Sevastapol 44 o N latitude) Ukraine, n June of 1942. The projectiles were 80 cm (-31.5") in diameter, and had masses p to 7100 kg. One particular projectile (which we will analyze here)(see iagram below) had a mass of 4800 kg (-5.3 tons), amuzzle velocity (vp) of 820 m/s, and was reported o have a range of 48 km (on impact t reportedly produced a crater 30 ft deep and 30+ ft across). For the purpose of this analysis suppose hat Schwer Gustav was ocated at 44o N latitude and was firing (aimed) due North, with a barrel nclination of 30o up from the horizontal. You may assume hat the terrain is absolutely lat. You may also consider standard ravity (9.S1 m/s2) as being valid at this location, and you DO NOT NEED TO CONSIDER TFIE VARTATION IN GRAVITY WITH TFIE ALTITUDE OF THE PROJECTILE (i.e. treat gravity as constant n this problem). You may also assume that you can neglect air resistance. Youwill have o make some other "EngineeringAssumptions/Approximations" tere (e.g. what terms you can neglect and what you should keep). Some are more acceptable han others. Please cleorly state what your assumptions are. Neglecting the spin of the earth and using standard ravity of 9:9.81 [m/s2] i.e. usingwhat you learned in basic dynamics): A) What is the time of flight for the projectile? t' B) What are he expected x,y) coordinates elative o the cannon of where his projectile will land? (using tl-du. east, 1t due north, and zt-vertical). { No w considering he rotation of the earth(but neglecting he change n gravity with altitude): C) Produce he scalar hreeequations of motion (i.e. Newton's 2no aw of Motion)(one associated ith each of the i , ,k directions) numerical alue) - '; n From the k equation, what is the actually apparent acceleration f gravity, Z (numerical value)? ) E) F ) G) F ) A From the j equation, what is the apparent acceleration, (numerical value)? What is finaly location of the mpact? 'r From the i equation, what s your estimate f the apparent acceleration, ? (value)' , is final x location of the mpact? 15 pts) NEGL€(.r AeP-, kF-StSt'Aasq-\. g s ,|1f {, .1h'& ?-'' .? '.,I 1"'.: 9.'} i *" t-nr ly !,,r l t" : s: 1{.},"t N :f, = ?,6, " * tra credit!!! What y,=fr,= 83-Q o = ltg.r't% A.A{=8€*S.' , qtt; n / s = Z , a\ t,*;"_L.'?*J = *_t*'" :,:jj:,,'/= pff,f* F ) r Y,tt = i lto't''t%,lia n .{?se-r}' ?I:E t1 rr i l= t N6 c ) e - = Prr5"t..l l P ' . ':a?N'a y ' t 'iir, + 'frrl , *A n * Ft " + ' , 4 . r - f , ,/*1# L+ l X,.. i,t'- X ,f - \ ii-\i+* f ' t .l}?Frfi"i$ruj'-,:+[j " 1 zr:ilE ;p-X S.r,r r Yruj' 1l '*u:i )t -"t-f ilz-Tf+ Jt ' l'{-r. ;/ - z n,"ii| 'r- v = * t' 7 e' *ls' ^f.n = {: ^ X, : = '.'y "; : tu'j: + = * , , * - \ tr:2.?I ' t , n I {2t ir: +' :93.8.3 v l l r l t -- s:'r"'r C y 5 . * 4 +?jlL*-'5u I = *o,ote?'A' r) v(*i]- Yrir +i$;f E ,7t* *:i*ti::':ilg: ff I *#{:l f g zn{i"sr * [ ? " +xtJer]

Exam1_2009_Solution2

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Page 1: Exam1_2009_Solution2

 

Problem 1

(70 points)

The most

powerful

cannon o ever

seeaction

was

"Schwer

Gustav"

(Heavy

Gustav) which was used by

'

Germany

n the siegeof Sevastapol

44o

N latitude) Ukraine,

n June

of

1942.

The

projectiles

were

80

cm

(-31.5")

in diameter,and had masses p to

7100

kg. One

particular

projectile

(which

we will analyze

here)(see iagrambelow) had a massof

4800

kg

(-5.3

tons), amuzzle

velocity

(vp)

of 820 m/s, and

was

reported o

have

a

range

of

48 km

(on

impact t reportedly

produced

a crater

30 ft deepand 30+ ft across).

For the

purpose

of

this analysis

suppose hatSchwer

Gustav

was ocatedat 44o

N

latitude

and was firing

(aimed)

due North, with a barrel

nclination

of 30oup

from the horizontal. You

may assume hat the

terrain

is

absolutely

lat.

You

may

also

consider

standard

ravity (9.S1

m/s2)as

being valid at this

location, and

you

DO NOT NEED TO CONSIDER TFIE VARTATION IN

GRAVITY WITH

TFIE

ALTITUDE OF THE

PROJECTILE

(i.e.

treat

gravity

as constant

n

this

problem).

You may also assume

that

you

can neglectair resistance.

Youwill have o

make

someother

"EngineeringAssumptions/Approximations"

tere

(e.g.

what terms

you

can neglect and what

you

should keep).

Some

are more acceptable han others. Please cleorly state what

your

assumptions

are.

Neglecting the spin of the earthand using standard

ravity

of

9:9.81

[m/s2]

i.e.

using what

you

learned

in basicdynamics):

A) What is the

time of flight for

the

projectile?

t'

B) What are

he expected

x,y)

coordinates elative o the

cannonof where his

projectile

will

land?

(using

tl-du. east,

1t

due

north, and

zt-vertical).

{

Now

considering he

rotation

of the earth(butneglecting

he change

n

gravity

with altitude):

C)

Produce he scalar

hree equations

of motion

(i.e.

Newton's

2no aw of Motion)(one associated ith

eachof

the i

,

,k

directions)

numerical

alue)

-

';

n

From the k

equation,

what

is the actually apparent

acceleration f

gravity,

Z

(numerical

value)?

)

E)

F)

G)

F)

A

From the

j

equation,what is the apparent acceleration,

(numerical

value)?

What

is finaly locationof the

mpact?

'r

From

the i equation,

what s

your

estimate f the apparent

acceleration, ?

(value)'

,

is final x locationof the

mpact?

15 pts)

NEGL€( . r

AeP- ,

kF-StSt 'Aasq- \ .

g s

,|1f

{,

.1h'&?-''

.?

'.,I

1"'.:

9.'}

i

*"

t-nr

ly !,,r

l

t" :

s:

1{.},"t

N

:f,

=

?,6,

"

*

tra credit !!! What

y , = f r , =

83 -Q

o

=

l t g . r ' t%

A.A {=8€*S . '

,

q t t ;

n / s

=

Z,

a\ t,*;"_L.'?*J

=

*_t*'"

:,:jj:,,'/=

pff,f*

F)

r

Y, t t

= i

l t o ' t ' ' t% , l i a

n

. {?se - r } '

? I :E

t1

rr

i l =

t

N 6

c )

e -

=

P r r 5 " t . . l

l P

' .

' : a ? N ' a

y ' t

'iir,

+

'frrl

,

*An

*

Ft"

+

' , 4

. r

- f ,

, / * 1 #

L+ l

X , . .

i , t ' -

X

,f

- \

i i - \ i+*

f '

t

. l } ?F r f i " i $ ru j ' - , : + [ j

" 1

z r : i l E

; p - X

S . r , r

r

Y r u j '

1 l

' * u : i

)t

- " t - f

i l z -T f+

Jt'

l'{-r.

;/

-

z

n,"ii|

'r-

v

=

*

t'

7

e'

*ls'

^ f .n

=

{:

^

X, :

=

'. 'y

"; :

t u ' j :

+ = *

,

,

* - \

t r : 2 . ? I

'

t , n

I

{ 2 t i r : + '

: 9 3 . 8 . 3

v l

l r l

t

- -

s : ' r " ' r

Cy

5.*

4

+ ? j l L * - ' 5 u

I

=

* o , o t e ? ' A '

r ) v(* i ] -

Yr i r

+i$; f

E ,7t*

*:i*ti::':ilg:

ff I

*#{:l

f

g

zn{ i "sr

*

[? "

+xtJer ]

Page 2: Exam1_2009_Solution2