# Circular Motion

Gold Member
Hi. When a plane travels in a vertical circular loop, what is the provider of the centripetal force, required to produce the circular motion?

At the top of the loop, there is gravity acting towards the center of the circle, so id assume that this is part of it, but what about at the bottom and sides of the circle? Gravity no longer acts towards the center of the circle, since it is always directed downwards. This is where my confusion arises.

Thanks for the help,
Dan.

denverdoc
What other forces are acting on the plane? Hint: there are a total of 4, couple of which have a bearing besides gravity.

Gold Member
Well there would also be air resistance, but in this case, im neglecting air resistance for the simplicity of the situation. Im just focusing on the force contributing to the centripetal force.

denverdoc
Ok, very good, thats one, but unlikely to help in this circumstance. You could just google a search for forces during flight, or think about why you hear what you do, assuming you have been aboard an aircraft. I'm not trying to make your life miserable, but this forum is dedicated to education. This takes effort on both the part of the teacher and student.

Gold Member
Well aswell as air resistance and gravity, there will be a force provided by the engines, or a thrust as ive heard it called before.

Would the final one be a force opposing the gravity?

denverdoc
Its called lift! Without it you are a bus too big to use the highway.

Gold Member
Ahh ok.

Im still a bit confused though. When travelling in a vertical loop, do both the lift and gravity affect the centripetal force?

Mentz114
Anything that travels in a circle experiences centripetal force. It is the reaction to the forces that keep the path circular. The pilot keeps the plane in it's path using the power of the engines.

Staff Emeritus