Massive Cable

  • #1

Homework Statement


A massive steel cable drags a 20.0 kg block across a horizontal, frictionless surface. A 90.0 N force applied to the cable causes the block to reach a speed of 3.60 m/s in 2.40 s.
What is the difference in tension between the two ends of the cable?

Homework Equations



F=ma
a=v/t

The Attempt at a Solution



a=3.6/2.4= 1.5 m/s2

90N=m*1.5
m=60
m(block)=20kg
m(cable)=40kg

F=40*1.5=60

90-60=30

Just looking at the numbers it doesnt look right

Thanks all for your help
 
Last edited:

Answers and Replies

  • #2
PhanthomJay
Science Advisor
Homework Helper
Gold Member
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Homework Statement


A massive steel cable drags a 20.0 kg block across a horizontal, frictionless surface. A 90.0 N force applied to the cable causes the block to reach a speed of 3.60 m/s in 2.40 s.
What is the difference in tension between the two ends of the cable?

Homework Equations



F=ma
a=v/t

The Attempt at a Solution



a=3.6/2.4= 1.5 m/s2yes

90N=m*1.5
m=60
m(block)=20kg
m(cable)=40kgyes

F=40*1.5=60 this is F_net

90-60=30no

Just looking at the numbers it doesnt look right

Thanks all for your help
looks like you isolated the rope and came up with the NET force on the rope. Try drawing a FBD of the block. Or identify all forces acting on the rope.
 

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