Physics 53 To 55 PDF
Physics 53 To 55 PDF
Physics 53 To 55 PDF
Mech
Name
HW-53
a.
Eafth.
i. As the ball falls from hito h1, does the total energy of
Consider system S, consisting of the ball and the
l'' -
u=0
- - -
Earlh
hi
lt'
--
T,Y =;
Earth
ii.
l:
totol
Stydent
ene?gy
of system S increases."
2: .f think thot the chonge in potentiol energy of the system is zero becouse
the distoncethe boll moves is smoll compored to the size of the eorth. The
chonge in total eneryy of system 5 is equol to the chonge in kinetic energy of
the ball."
If any of these
iv.
v.
Solve your equation from part iv for the final speed of the ball. Is your result consistent
with what you would obtain using kinematics and your knowledge of the acceleration due
to gravity near the Earth's surface? If not, resolve the inconsistency.
'r/
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Custom
2nd
Mech
Consentation of energy
HW-54
b.
i.
As the ball falls from htto hr, does the total energy of system T increase, decrease, or
stay the same? Explain by considering the net work on system T.
ii.
Write an expression for each of the following quantities in terms of the given variables
and any physical constants.
.Chonges
Explain how your answer to the third bullet of pag b.ii is consistent with this statement.
If it is not consistent, how could you change it to make it consistent?
c.
iv.
Write an equation that relates the three expressions from part b.ii.
v.
Solve the equation from part b.iv for the final speed of the ball.
Check that your answer to part b.v is consistent with your answer to part a.v.
the inconsistency.
If not, resolve
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Custom 2"d
d.
Mech
Name
Conseraation of enerry
HW-55
i.
Describe the effect the Earth has on the energy of system S (i,e., when the Earth ls part of
the system).
ii.
Describe the effect the Earth has on the energy of system T (i.e., when the Earth is not
part of the sYstem).
Z. A student observes an apple falling from a tree and makes the following statement:
"The Eorth exerts o f orce on the opple, the force of grovity. The Eorth does work on the opple.
I con write the following eguotion tq describe this inferoction:
oWoppu,cqrrh
.The
= AK + AUsrov
wonk done by the Eorth increoses the opple's kinetic anergY snd decneoses its potentiol
energy,n
'
What mistake is this student making? How would you colrect the student's equation?
a.
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