# Vectors with mechanics question

https://www.quora.com/profile/Bravewarrior/p-157991506
Here is the question I am stuck on. How can I figure out if the plane is ascending or descending? (from part b)

Thanks!
Original post by pigeonwarrior
https://www.quora.com/profile/Bravewarrior/p-157991506
Here is the question I am stuck on. How can I figure out if the plane is ascending or descending? (from part b)
Thanks!

Its initially in level flight (zero vertical velocity) so which way is the net vertical force acting which willl result in a non zero vertical velocity in that direction.
Original post by pigeonwarrior
https://www.quora.com/profile/Bravewarrior/p-157991506
Here is the question I am stuck on. How can I figure out if the plane is ascending or descending? (from part b)
Thanks!

Find the resultant of the vertical components of forces to figure out if acceleration is negative or positive.
Thank you so much everyone! 🙂
The vertical components would be the lift and weight force. Weight is 1200 x 9.8 which is 11760 N. They gave me lift in the question as 11000k. How do I figure out the resultant force from this?
Original post by pigeonwarrior
The vertical components would be the lift and weight force. Weight is 1200 x 9.8 which is 11760 N. They gave me lift in the question as 11000k. How do I figure out the resultant force from this?
Considering all the vertical components, (including north)
resultant force in y: -1800+300+11000+500-(1200x 9.81)
This comes out to be negative, so the vertical component of acceleration on plane is negative, hence plane is descending.
(edited 3 months ago)
Original post by WordsFiddle
Considering all the vertical components, (including north)
resultant force in y: -1800+300+11000+500-(1200x 9.81)
This comes out to be positive, so the vertical component of acceleration on plane is positive, hence plane is ascending.

You can then use the magnitude of acceleration calculated in part a to figure out the angle: let you answer in part a be A and the vertical component of acceleration calculated in part b be A', then A sin(angle)= A'.
They have asked for the obtuse angle so answer accordingly
Original post by pigeonwarrior
The vertical components would be the lift and weight force. Weight is 1200 x 9.8 which is 11760 N. They gave me lift in the question as 11000k. How do I figure out the resultant force from this?

Vertical motion/force is in the "k" direciton so just consider (add the signed coefficients) the k components in Thrust and Lift as well as the weight which acts downwards to get the resultant force.
(edited 3 months ago)
Thank you so much everyone once again, I finally get it now 😁