Tension & Friction Interaction

[naoke27]

A 50kg woman dangles a 50kg mass from the end of a rope If she stands on a frictionless surface and hangs the rope over a cliff with a pulley, the tension in the rope will be (ignore frictional forces):
0N vs (250N) vs 500N vs 1000N

Another twist to this question is to change the weight of the person to 100kg and leave everything else the same.
250N vs (333N) vs 500N vs 667N

I looked at the question, drew a diagram and thought the weight of the person was irrelevant.Thus, I solved for them both without regard to the weight of the person. I simply looked and saw that the gravitational force was equal to tension in the rope, and both were 500N.

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[milski]

That would be true only if the person was stationary. On a frictionless surface both the weight and the person are accelerating. The net force on the whole system is as you said 500 N. The mass of the system is 50+50=100 kg and the acceleration is 500/100=5 m/s². From F=am the force on the woman (which is only the tension force) is 50*5=250 N.

 

[AdmAckbar]

Makes sense but first run through I did it the same way as OP. This is a tricky question, what source did you get it from?

 

[naoke27]

This is from EK 1001 Physics