Dropping Package Homework: Newton's 2nd Law & Position in Flight

  • Thread starter Thread starter Bashyboy
  • Start date Start date
AI Thread Summary
Newton's second law is applied to determine the bundle's position as it falls from the plane, neglecting air resistance. For part b, the pilot must drop the bundle a specific horizontal distance before reaching the raft, calculated using given values of speed and height. The discussion raises a question about whether to use specific numerical values or derive a general solution for part c, focusing on the time interval for the drop. It is clarified that the specific speed from part b should be used to calculate how a delay in dropping affects the landing position. Overall, the key focus is on accurately determining the drop distance and timing to ensure the bundle lands within a designated area near the raft.
Bashyboy
Messages
1,419
Reaction score
5

Homework Statement


A plane, which is flying horizontally at a constant speed v0 and at a height h above the sea, must drop a bundle of supplies to a castaway on a small raft

a) Write down Newton's second law for the bundle as it falls from the plane, assuming you can neglect air resistance. Solve your equations to give the bundle's position in flight as a function of time t.

b)How far before the raft (measured horizontally) must the pilot drop the bundle if it is to hit the raft? What is this distance if v0 = 50m/s, h = 100m, and g ≈ 10m/s^2?

c)Within what interval of time (±Δt) must the pilot drop the bundle if it is to land within ±10m of the raft?


Homework Equations





The Attempt at a Solution



I believe I properly solved parts a) and b). For part c), to calculate the time interval, am I suppose to use the specific numerical values given in part b), or am I suppose to derive a general solution? If it is the latter case, can I suppose the separation between the plane and drop-site is d? I am not certain if that would be of much avail, however, for the distance be those two things is constantly shrinking.
 
Physics news on Phys.org
The general solution for c) is extremely simple. Find it.
 
Bashyboy said:
For part c), to calculate the time interval, am I suppose to use the specific numerical values given in part b), or am I suppose to derive a general solution? If it is the latter case, can I suppose the separation between the plane and drop-site is d? I am not certain if that would be of much avail, however, for the distance be those two things is constantly shrinking.
I agree it's not clear whether you are supposed to use the speed given in part b. Since you are given a specific distance range, I expect you are. You don't need to know the actual separation. All the question is asking is this: if the drop is delayed by Δt how much difference will that make to the landing position?
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top