In: Physics
Two spaceships taxiing into starfleet drydock follow linear trajectories. Rocket 1 is initially at the position x1= (100m, 0m, 200m) and has a constant velocity given by the vector v1= (-100m/s, 200m/s, 0m/s). Rocket 2 is initially at the position x2= (200m, -100m, 100m) and has a constant velocity given by the vector v2?= (100m/s, 100m/s, 100m/s).
a.) Write the equations for the linear trajectories followed by both the rockets.
b.) Find the distance of the closest approach to the station hub located at (0m, 0m, 0m) for rocket 2.
c.) Find the minimum distance between the rockets.
given two spaceships
Rocket 1:
x1 = (100,0,200)m
v1 = (-100, 200,0) m/s
Rocekt 2:
x2 = (200,-100,100) m
v2 = (100,100,100)m/s
a. for rocket 1
position as a funciton of time is given by
r1 = x1 + v1*t = (100 - 100t, 200t, 200)
similiarly
for rocekt 2
r2 = (200 + 100t , -100 + 100t, 100 + 100t)
hence in parametric form
r1 = (100 - 100t)i + 200t j + 200k
r2 = (200 + 100t)i + (-100 + 100t)j + (100 + 100t)k
where i , j and k are unit vectros along x, y and z directions
hence
for rocekt 1
x = 100 - 100t
y = 200t
z = 200
hence
x = 100 - 100*y/200
200x = 200,00 - 100y
2x = 200 - y, z = 200
for rocekt 2
x = 200 + 100t
y = -100 + 100t
z = 100 + 100t
y + z = 200t = (x - 200)2
y + z = 2x - 400
2x - y - z = 400
b. for rocekt 2, distance of closest approach to the dock located at (0,0,0)
is
d2 = 400/sqroot(4 + 1 + 1) = 163.29931618 m
c. distance betwwen two rockets at time t is given by
d = sqrt((100 - 100t - 200 - 100t)^2 + (200t + 100 - 100t)^2 + (200 - 100 - 100t)^2)
d = 100*sqrt(3 + 6t^2 + 4t)
d = 100*sqrt(6t^2 + 4t + 3)
the minimum happens when
6t^2 + 4t + 3 is minimum = M
dM/dt = 0
12t + 4 = 0
t< 0
hence not possibel
hence
hence for t = 0, the distnac eis minimum
d = 100*sqrt(3) = 173.2050807568 m