Question 16b ext2 2022 (1 Viewer)

[colt2650]

Does anyone have a solution which takes into account that the projectile when returning to the plane has the resistive force opposing it.
The solutions I have seen have the resistive force acting downward for the entire flight (which is not so).
Downward positive My = Mg - 0.1Mv

Any comments appreciated

 

[Vall]

Pretty sure that got discussed in this thread https://boredofstudies.org/threads/maths-extension-2-thoughts-and-feelings.401616/
If I remember correctly, the consensus was that for the downwards trip the velocity now going down) is defined as positive so the air resistance (which is still negative) opposes the velocity.

 

[colt2650]

Perfect I understand
When the projectile begins to return, the velocity becomes negative and as the resistive force is proportional to v, it will change signs and therefore oppose the motion.
Of course this would not happen if the resistive force is proportional to v squared.
Thanks heaps