QUIZ

3

PHYSICS

152

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5

points

each. Show your work

to

receive

partial

credit.

1) A

stone

is

attached

to

a

string

and

whirled in a vertical circle of radius 1.5m.

At

both

the

exact

top

and

exact

bottom

of

the

circle,

the

tension in

the

string

is 2.5 times

the

stones weight.

What

is

the

ston

e's speed

at

the

top

and

at

the

bottom?

(Answers are top,

bottom)

l

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b) 4.70

mis,

7.17

mls

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mis,

3.25

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d) 7. 17

mis,

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2)

Planets

A (mass

rnA)

and

13

(mass

mE=

3mA) are a dis

t'

ance

rA

and

rE=2.

5rA

from

their

host

f)YA

star.

What

is

the

ratio

of

the

forces between

the

star

and

the

planets

(F AIFE)? I

{6

~

a).48

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b) 1.37

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d)

3.21

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te,

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(?SC.)'.1-

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~;1.0~

3)

State

Kepler's

Third

Law. '\ f

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+he

St{yIJ.v..reS

of-

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u,-!::)v

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wo p

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ne

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nce

s )

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(Y'ICo..-r \ -

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:=

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4) A

pendulum

bob

of mass 2 g is pulled

to

a height of

15

cm.

What

is its

potential

energy?

a) .292 J

-3

\

~E

:::

(Y\C

y

'\)

(Y\::-

')

[

~:::

JX

I~

-3,~(ff-

~

0

h:::.

lS--cVYl:::;

0·1::;

(Yl

c) 2.95 J

,\

._)

__

d)_296 J ?

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:;.

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rn/)") C

ohm

Date

:

11/4/2011.