A 80-kg person stands at rest on a scale while pulling vertically downwards on a rope that is above them. Use g = 9.80 m/s2. With what magnitude force must the tension in the rope be pulling on the person so that the scale reads 25% of the persons weight?

The tension in the rope is 588 N

Explanation:

I have attached a free body diagram of the problem.

First we calculate the force applied downwards by the person's weight:

If the scale reads a 25% of the person' weight:

which is the same value (but opposite) to the effective weight of the persons ()

The other 75% of the total weight is the force of the rope pulling the person upwards.

To verify, we can use 1st Newton's law

∑F = 0

it doesn't. it was imagined up in the middle ages.