#$&*
course Phy 121
A rubber band begins exerting a tension force when its length is 8 cm. As it is stretched to a length of 10 cm its tension increases with length, more or less steadily, until at the 10 cm length the tension is 3 Newtons. Between the 8 cm and 10 cm length, what are the minimum and maximum tensions?
answer/question/discussion:
minimum tension= 0N
Maximum tension=3N
#$&*
Assuming that the tension in the rubber band is 100% conservative (which is not actually the case) what is its elastic potential energy at the 10 cm length?
answer/question/discussion:
Fnet*ds=PE
3N*2cm=6J
#$&*
If all this potential energy is transferred to the kinetic energy of an initially stationary 20 gram domino, what will be the velocity of the domino?
answer/question/discussion:
dWnet=(1/2)M*vf^2-(1/2)M*v0^2
6J=(1/2)(.02kg)*vf^2-(1/2)(.02kg)(0cm/s)^2
vf=24.5cm/s
#$&*
If instead the rubber band is used to 'shoot' the domino straight upward, then how high will it rise?
answer/question/discussion:
v0=24.5m/s
vf=0m/s
ds=?
A=-9.8m/s^2
vf^2=v0^2+2*a*ds
(0m/s)^2=(24.5m/s)^2+2*(-9.8m/s^2)*ds
ds=31m
#$&*
For University Physics students:
Why does it make sense to say that the PE change is equal to the integral of the force vs. position function over an appropriate interval, and what is the appropriate interval?
answer/question/discussion:
Self-critique (if necessary):
------------------------------------------------
Self-critique rating:
________________________________________
#$&*
@&
See also my notes on the preceding seed question.
3 N is the maximum, not the average tension for this interval.
6 N * cm is not 6 Joules.
You would also want to understand that last question in terms of the conversion of elastic potential energy to gravitational potential energy.
`gr99
*@
#$&*
course Phy 121
A rubber band begins exerting a tension force when its length is 8 cm. As it is stretched to a length of 10 cm its tension increases with length, more or less steadily, until at the 10 cm length the tension is 3 Newtons. Between the 8 cm and 10 cm length, what are the minimum and maximum tensions?
answer/question/discussion:
minimum tension= 0N
Maximum tension=3N
#$&*
Assuming that the tension in the rubber band is 100% conservative (which is not actually the case) what is its elastic potential energy at the 10 cm length?
answer/question/discussion:
Fnet*ds=PE
3N*2cm=6J
#$&*
If all this potential energy is transferred to the kinetic energy of an initially stationary 20 gram domino, what will be the velocity of the domino?
answer/question/discussion:
dWnet=(1/2)M*vf^2-(1/2)M*v0^2
6J=(1/2)(.02kg)*vf^2-(1/2)(.02kg)(0cm/s)^2
vf=24.5cm/s
#$&*
If instead the rubber band is used to 'shoot' the domino straight upward, then how high will it rise?
answer/question/discussion:
v0=24.5m/s
vf=0m/s
ds=?
A=-9.8m/s^2
vf^2=v0^2+2*a*ds
(0m/s)^2=(24.5m/s)^2+2*(-9.8m/s^2)*ds
ds=31m
#$&*
For University Physics students:
Why does it make sense to say that the PE change is equal to the integral of the force vs. position function over an appropriate interval, and what is the appropriate interval?
answer/question/discussion:
Self-critique (if necessary):
------------------------------------------------
Self-critique rating:
________________________________________
#$&*
@&
See also my notes on the preceding seed question.
3 N is the maximum, not the average tension for this interval.
6 N * cm is not 6 Joules.
You would also want to understand that last question in terms of the conversion of elastic potential energy to gravitational potential energy.
&#Please see my notes and submit a copy of this document with revisions, comments and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
Be sure to include the entire document, including my notes. &#
*@