cq_1_121

#$&*

phy 201

Your 'cq_1_12.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

CQ_1_12.1_labelMessages

Asst 12 question 1

Masses of 5 kg and 6 kg are suspended from opposite sides of a light frictionless pulley and are released.

• What will be the net force on the 2-mass system and what will be the magnitude and direction of its acceleration?

answer/question/discussion: ->->->->->->->->->->->-> :

5kg

6kg

11kg

A=9.8m/s

9.8*5=-49newtons

9.8*6= 58.8newtons

Fnet=-49+58.8newtons

Fnet=9.8newtons

F=m*a

f/m=a

9.8newtons/11kg= .89m/s/s

#$&*

• If you give the system a push so that at the instant of release the 5 kg object is descending at 1.8 meters / second, what will be the speed and direction of motion of the 5 kg mass 1 second later?

answer/question/discussion: ->->->->->->->->->->->-> :

v0= 1.8m/s

dt=1

-9.8newtons

5kg

-9.8/5=-1.96m/s^2

A=dv/dt

A*dt=dv

-1.96m/s^2*1s=-1.96m/s

@&
The two masses are still attached and are moving together, so the mass of the system does not change. As soon as the push is over, the net force is still the same as before and so therefore is the acceleration.
*@

Dv=-1.96

Vf=-3.76

vAve=1.8+-3.76/2=

vave=-.98m/s

vAve=ds/dt

vAve*dt=ds

-.98m/s*1s= -.98m

#$&*

• During the first second, are the velocity and acceleration of the system in the same direction or in opposite directions, and does the system slow down or speed up?

answer/question/discussion: ->->->->->->->->->->->-> :

opposite directions and it speeds up just in the opposite direction

#$&*

*#&!

@&
Good solution on the first part.

On the second part the acceleration is the same as on the first (see my note). So take a few minutes and recalculate those results; if this changes your answer to the last question you should revise it also.

&#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.

cq_1_121

Your 'cq_1_12.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

** CQ_1_12.1_labelMessages **

@& The two masses are still attached and are moving together, so the mass of the system does not change. As soon as the push is over, the net force is still the same as before and so therefore is the acceleration. *@

@& Good solution on the first part. On the second part the acceleration is the same as on the first (see my note). So take a few minutes and recalculate those results; if this changes your answer to the last question you should revise it also.

&#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.

CQ_1_12.1_labelMessages

@&
The two masses are still attached and are moving together, so the mass of the system does not change. As soon as the push is over, the net force is still the same as before and so therefore is the acceleration.
*@

@&
Good solution on the first part.

On the second part the acceleration is the same as on the first (see my note). So take a few minutes and recalculate those results; if this changes your answer to the last question you should revise it also.

&#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.