Kinetic frictions, pulleys, and Newton's third law

  • Thread starter sdoi
  • Start date
  • #1
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Homework Statement


Block A and B are connected by a string passing over an essentially frictionless pulley. (Block A is on a horizontal plane, while block B is suspended in the air) When the blocks are moving block A experiences a force of kinetic friction of magnitude 5.7N. If mA= 2.7kg and mB= 3.7kg calculate the magnitude of:
(a) The acceleration of the blocks
(b) The tension in the string


Homework Equations


ƩFx=ma(x)
ƩFy=ma(y)
a(x)= ƩFx/m
Fnet(a)= Ft=Fk
Fnet(b)= Fg-Ft
Ft(b)=Ft(a)



The Attempt at a Solution


ƩF(a)= Ft-Fk
= Ft- 5.7N
ƩF(b)= Fg-Ft
= mg-Ft
=(3.7kg)(9.8N)-Ft
=36.26N-Ft
 

Answers and Replies

  • #2
Spinnor
Gold Member
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346
Does the following look like I'm on the right track?
 

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