Find the Difference in Tension: Steel Cable & 20kg Block

[madskier8806]

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 doesn't look right

Thanks all for your help

 

[PhanthomJay]

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[/color]

90N=m*1.5
m=60
m(block)=20kg
m(cable)=40kgyes[/color]

F=40*1.5=60 this is F_net[/color]

90-60=30no[/color]

Just looking at the numbers it doesn't 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.