A massive steel cable drags a 20kg block across a horizontal, frictionless surface. A 100N force applied to the cable causes the block to reach a speed of 4.2m/s in a distance of 2.1m .

Question

What is the mass of the cable?

Answer 1

s = v^2/2a, so

4.2^2/2a = 2.1
a = 4.2 m/s^2

F=ma, so
100 = (20+m)(4.2)
m = 3.8 kg

Answer 2

A steel cable lying flat on the floor drags a 20 kg block across a horizontal, frictionless floor. A 100 N force applied to the cable causes the block to reach a speed of 4.1 m/s in a distance of 1.9 m.

Answer 3

ans is absolutely right!