Proj/Circ past question help (1 Viewer)

[erucibon]

2001 Q18 c)
describe and compare the vertical forces acting on A and B at their maximum heights.

I worked out that for A, the force is gravitational force which is equal to mg = 294N. For B, I thought that the force acting on it would be gravitational and tension(??) both downwards which add to give fnet = fc = 480N. Since gravitational is 294N, tension(??) is 186N.

When I tried to check my answers on https://arc.nesa.nsw.edu.au/standards-packs/SP01_15330/ (could not find other worked solutions)
all the sample answers had different answers and one of them agreed with my answer. Could someone please clear up what the actual answer is and what the other force actually is?
Thanks!

 

[Drdusk]

View attachment 27940
2001 Q18 c)
describe and compare the vertical forces acting on A and B at their maximum heights.

I worked out that for A, the force is gravitational force which is equal to mg = 294N. For B, I thought that the force acting on it would be gravitational and tension(??) both downwards which add to give fnet = fc = 480N. Since gravitational is 294N, tension(??) is 186N.

When I tried to check my answers on https://arc.nesa.nsw.edu.au/standards-packs/SP01_15330/ (could not find other worked solutions)
all the sample answers had different answers and one of them agreed with my answer. Could someone please clear up what the actual answer is and what the other force actually is?
Thanks!

You should just go with mv^2/r. With v and r obviously being given. Realistically there could even be an electric force on the object that they didn’t mention or whatever

So yes you are right the force on B is mv^2/r = 480N

The other 2 answers are incorrect but I guess it still counts as a band 5/6 response.