An observer on earths sees spaceship 1 fly at 0.80c. 9 years later according to the observer on earth, spaceship 2 flies by earth at 0.80c, traveling in the same direction as the first. both spaceships continue to travel with constant velocities.
1) an observer in spaceship 1 observes earth to pass spaceship 2 years after earth passed spaceship 1.
a)7.2
b)10
c)12
d)15
e)20
an observer in spaceship 1 observes spaceship 2 to be light-years away.
a)7.2
b)10
c)12
d)16
e)20

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s