Tension in UCM (1 Viewer)

[english? ensquish]

When an object in UCM at the top of the circular motion, why is Ftension= Fc -Fg if both Fc and Fg act downwards - Fc acts towards the centre and Fg is down

And then when it’s at the bottom, it’s Ft= Fc+ |Fg|?? Why is that?

i also don’t get tension in physics …



i thought it would’ve been Fc+Fg but it’s not, and I searched online but it says Ft= Fc-Fg too soo

 

[kractus]

Fc is a fancy way of expressing the net force.
At the bottom, there is weight force (Fg) downwards and tension (Ft) upwards.
Hence Fc = Ft - Fg.
Thus, Ft = Fc + Fg.

At the top, the net force (Fc) is Fg + Ft as both are in the same direction.
Hence Fc = Fg + Ft.
Thus, Ft = Fc - Fg.
You're thinking of Ft as the net force when in reality Fc is net force.

 

[wizzkids]

Perhaps this vector diagram will help you to visualise how the tension changes when an object is whirled vertically in a gravitational field.

If the object is whirled at the critical speed, at the top of the swing the tension will be close to zero.
At the bottom of the swing the tension will be two times the weight of gravity.
Does that help you to visualise what is going on?

 

[english? ensquish]

Ohh wow I feel like I just went through catharsis or smth thank both of you