This is 2 problems that continue one another; I solved the first one but do not understand the second.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

A 100kg man dangles a 50kg mass from the end of a rope. If he stands on a frictionless surface and hangs the mass over a cliff with a pulley, the tension in the rope will be: (Note: Ignore any frictional forces) [SOLVED]

In the question above, as the mass becomes infinitely large, the man's acceleration becomes:

A. 5m/s^{2}

B. 10m/s^{2}

C. 20m/s^{2}

D. infinite

2. Relevant equations

F = ma

3. The attempt at a solution

The solution to the first problem:

50g = (50+100)a

a = g/3 ~ 3.33

T = mass of man (a) = 100(3.33) = 333N

For the second problem:

Now the acceleration is directly tied to the mass of the block, so when it becomes infinite, I think the acceleration should be infinite.

However, in the answers it says: "B is correct. No matter how large the mass gets, its acceleration can never be greater than g, because it is gravity that is acting on it. Of course, the man will not be accelerated faster than the mass."

They go on to repeat this method again in the next problem. I don't really understand how the man's acceleration would still be finite with a block of infinite mass.

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# Homework Help: Pulleys and Mass becoming infinitely large

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